INDEX of the challenge archive -

[401 as of 4/7/20]


A
2D Algebra Tiles                              Families of functions
3D Algebra Blocks                             Families of functions

6 objects in search of conjecture(s)          Functions on the Domain of Shapes

A 3D Protractor ?                             Functions on the Domain of Shapes

Absolute value functions & quadrilaterals     Families of functions

A Bestiary of Curves [degree > 2]             Families of functions

A Car & 20 Questions: Parts I & II            Modeling & formulating
                                              Physics Nuggets


A Circular Conundrum                          Functions on the Domain of Shapes

A Cube Removed From A Cube                    Functions on the Domain of Shapes

Adding & subtracting uncertain measures       Number Sense & Computation...

Adult tickets & child tickets - I             Modeling & formulating

Adult tickets & child tickets - II            Modeling & formulating

A False Combining Rates Problem               Functions on the Domain of Shapes


A Gecko's Journey                             Functions on the Domain of Shapes

A Line & An Hyperbola                         Families of functions


Algebraic Tessellations                       Function as object

Analog Clock                                  Modeling & formulating

Age Problem Calculator                        Modeling & formulating

A Leaky Bathtub - a metaphor for...           Modeling & formulating                                                                           Physics Nuggets


A Merry-Go-Round Triangle                     Functions on the Domain of Shapes

Angle parameter space for Triangles           Parameter spaces

An Imposter Function                          Function as object

An Interesting Overlap                        Functions on the Domain of Shapes


An Area-Perimeter Exploration                 Functions on the Domain of Shapes


An Homage to Archimedes                       Functions on the Domain of Shapes

Annular ring                                  Functions on the Domain of Shapes

Another weigh to go !                         Modeling & formulating

                                              Physics nuggets

A Puzzling Object                             Imagine

A Puzzling Object - II                        Imagine

A Puzzling Problem                            Modeling & formulating

Archimedes’ Surprise                          Physics Nuggets

Archimedes - triangle & parabolic segment     Calculus applets

Archimedes & the Volume of a Sphere           Functions on the Domain of Shapes

Aristotle's Wheel                             Physics Nuggets

Area Perimeter Workbench                      Functions on the Domain of Shapes

A Run for Two                                 Modeling & Formulating
A Run for Two - revised                       Modeling & Formulating

Approximating Functions with polynomials      Families of functions

Assessing Understanding of Fraction Ordering  Number Sense & Computation...

A Swirl of Spirals                            Families of functions

A Tale of Two Orbits                          Physics Nuggets

Aubel's Theorem                               Functions on the Domain of Shapes

B

Bagels or Donuts                              Modeling & formulating

Baton twirl                                   Physics Nuggets

Believing is Seeing                           Imagine...

Between-ness in Addition & Subtraction        Number sense & Computation...

Between-ness in Multiplication & Division     Number sense & Computation...


Between-ness with rational numbers            Number sense & Computation...

Beyond the Median                             Functions on the Domain of Shapes

Bicycle Chain Math                            Modeling & formulating

Binary Search: "Looking for a needle..."      Number sense & Computation...

BOOMERANG !                                   Functions on the Domain of Shapes


Boundaries and Enclosures                     Functions on the Domain of Shapes


Build a million numbers                       Number sense & Computation...

Build & Fit – absolute value f'n I            Families of functions

Build & Fit – absolute value f'n II           Families of functions

Build & Fit – absolute value f'n III          Families of functions

Build & Fit – ellipse                         Families of functions

Build & Fit – hyperbola                       Families of functions  

Build & Fit – linear functions                Families of functions

Build & Fit – parabola                        Families of functions

Build & Fit – quadratic functions             Families of functions


Build a quadratic from a rectangle            Families of functions

Build a Triangle out of Altitudes             Functions on the Domain of Shapes

Build a Triangle out of Angle Bisectors       Functions on the Domain of Shapes

Build a Triangle out of Medians               Functions on the Domain of Shapes

Build a Triangle out of Medians - II          Functions on the Domain of Shapes


Building a Cardboard Box                      Functions on the Domain of Shapes
                                              Modeling & formulating


Building an 'Imposter' Function               Function as object

Burning Tent on an Elliptical Island          Functions on the Domain of Shapes


Butterfly Theorem                             Functions on the Domain of Shapes

By All means! - averaging 2 numbers           Number Sense & Computation...

By All means! - averaging 3 numbers           Number Sense & Computation...

C

Calculus workbench                            Families of functions

Carnot's Theorem                              Functions on the Domain of Shapes

Carpe diem - a day clock                      Modeling & formulating

'Circling the Square'                         Functions on the Domain of Shapes

Circle in a triangle                          Functions on the Domain of Shapes


Circle between quarter circles                Functions on the Domain of Shapes

Circles & ellipses in the {radius,...         Parameter Spaces


Circle & Square                               Parameter Spaces

Circular & Hyperbolic Trig F'ns               Families of functions


Circumenter finder                            Functions on the Domain of Shapes

Circumsphere of a Tetrahedron                 Imagine...


Classic napkin ring problem                   Functions on the Domain of Shapes

Coffee Mixture Problem                        Modeling & formulating

Coffee Mixture Problem - II                   Modeling & formulating

Coin Problem Workbench                        Modeling & formulating

Combining rates - I - Joe & Sam paint...      Modeling & formulating

Combining rates - I - Joe & Sam revisited     Modeling & formulating

Combining rates - upstream, downstream - I    Modeling & formulating

Combining rates - upstream, downstream - II   Modeling & formulating

Common Denominator Finder                     Parameter Spaces

                                              Number sense & Computation...

Common Factor Finder                          Parameter Spaces

                                              Number sense & Computation...

Composing Transformations                     Function as object

Composing w/ Exponential & Logarithmic...     Function as object


Composition - same as Translation... ?        Function as object

Conic Sections in Parameter Space             Parameter Spaces

Conjectures about Complex roots...            Function as object

Conjectures about...part II                   Function as object

Constructing Functions by sliding/…           Families of functions

Coupled Oscillators & Normal Modes            Physics Nuggets

Crowdedness                                   Modeling & formulating

Cubicality of Boxes                           Functions on the Domain of Shapes

D

Derivative explorer                           Families of functions

Digital Handball                              Physics Nuggets


Dimensional units                             Imagine...

Dimes & Quarters I                            Modeling & formulating

Dimes & Quarters II                           Modeling & formulating

Dimes & Quarters for Teachers                 Modeling & formulating

Disc-ness                                     Modeling & formulating

Disc Rolling on a Disc                        Functions on the Domain of Shapes

Disc Rolling inside a Disc                    Functions on the Domain of Shapes

Discovering Pythagoras                        Functions on the Domain of Shapes

Discovering the Law of Cosines                Functions on the Domain of Shape

Distances from three points                   Imagine...

DIY estimation - addition                     Number Sense & Computation...

DIY estimation - multiplication               Number Sense & Computation...

E

Elliptical Billiard Table                     Functions on the Domain of Shapes

'Elliptical' Trigonometric Functions          Families of Functions

Equilateral-ness of Triangles                 Modeling & formulating


Equilateral & Equiangular N-gons              Functions on the Domain of Shapes

Erehwon Coinage                               Modeling & formulating

Estimating Products - power drill             Number sense & Computation...

Estimating Sums - power drill                 Number sense & Computation...

Even and Odd Functions - I                    Function as Object
Even and Odd Functions - II                   Function as Object

Exploring the FOIL method                     Families of functions                                                                       Number sense & Computation...

Exploring Ordering of Fractions               Number sense & Computation...

Exponential Functions                         Families of Functions

Exponential & Quadratic have a race           Families of Functions

Euler's line                                  Functions on the Domain of Shapes

F

f(x) f'(x) puzzle                             Families of functions

f(x)/f'(x) puzzle                             Families of functions

f(x)+f'(x) puzzle                             Families of functions

Factoring Quadratic Functions                 Families of functions

                                              Number sense & Computation...

Falling Dominoes                              Physics Nuggets

Family Function Builder                       Families of functions

Fill your oil tank - a problem posing...      Modeling & Formulating

Filling Revolutionary Vessels                 Functions on the Domain of Shapes

Five Circles in a Square                      Functions on the Domain of Shapes

Fregier's Theorem                             Functions on the Domain of Shapes

Fuel Consumption Calculator                   Modeling & formulating

“Fraction Workbench”                          Number sense & Computation...

Football & Handball in Parameter Space        Physics Nuggets

                                              Parameter Spaces

Forced Damped Oscillator                      Physics Nuggets


Four Color Square                             Functions on the Domain of Shapes

Function Attribute Explorer                   Function as Object

…Function on the Space of Quadrilaterals      Functions on the Domain of Shapes

Function as Object – how they change I        Function as Object

Function as Object – how they change II       Function as Object

Function Table Builder                        Function as Object

G

Gardner's problem                             Functions on the Domain of Shapes

Gear train                                    Physics Nuggets

                                              Modeling & formulating

Gelfand's Horse                               Physics Nuggets

General word problem workbench                Modeling & formulating 

Generalizing the Marion Walter Theorem        Functions on the Domain of Shapes

Goldbach to and fro                           Imagine

Good fits - Bad models                        Modeling & formulating

Going On A Trip - a motion problem sandbox    Modeling & formulating

H

Hemisphere, Cone, Cylinder                    Functions on the Domain of Shapes

Horse tied to a barn                          Functions on the Domain of Shapes


Horse on Road and Field                       Modeling & formulating

                                              Physics Nuggets

Hens & Rabbits I                              Modeling & formulating

Hens & Rabbits II                             Modeling & formulating

Hens & Rabbits for Teachers                   Modeling & formulating

Heron's formula                               Imagine

How a DVD player works                        Modeling & formulating               

                                              Physics Nuggets


How are degrees & radians related?            Functions on the Domain of Shapes

How can f(x) equal f'(x)                      Modeling & formulating

How similar are...Linear functions?           Imagine

How similar are...Quadratic functions?        Imagine


How tall is the ...?                          Equations & Inequalities as…

I

“…in a Square”                                Functions on the Domain of Shapes

Incenter finder                               Functions on the Domain of Shapes


Inequality & Equation Explorer                Equations & Inequalities as…

Inscribing an Isosceles Triangle...I          Functions on the Domain of Shapes

Inscribing an Isosceles Triangle...II         Functions on the Domain of Shapes

Inverse Prime Factoring                       Number sense & Computation...

Inversion in a gold circle                    Functions on the Domain of Shapes

Isosceles Triangles                           Parameter Spaces

Isosceles Triangles - revisited               Parameter Spaces

Isosceles Triangle Factory                    Functions on the Domain of Shapes


Integral explorer                             Families of functions

J

Jack & Jill                                   Parameter Spaces

                                              Modeling & formulating

Joe T's theorem I                             Families of functions

Joe T's theorem II                            Families of functions

K

Keeping Pace                                  Modeling & formulating

                                              Physics Nuggets

Kite space                                    Parameter Spaces

L
Latitude & Longitude Explorer                 Functions on the Domain of Shapes

Linear & Angular Velocity                     Physics Nuggets

Linear Functions – parameter plane            Parameter Spaces

Linear functions & yellow bowties             Families of functions

Linear functions & quadrilaterals             Families of functions

Linear Inequalities Solved w/ Graphs &...     Equations & Inequalities as…

Lissajous –                                   Physics Nuggets

Locations on a Sphere                         Imagine...                                                                       Functions on the Domain of Shapes

Logs in a Trough                              Functions on the Domain of Shapes

M

Make a Cyclic Quadrilateral                   Functions on the Domain of Shapes

Many-answer addition                          Number sense & Computation...

Many-answer subtraction                       Number sense & Computation...

Mary's round trip                             Modeling & formulating


Meeting Up – on the road with red & blue      Modeling & formulating

Mean Value Theorem                            Function as object


Measuring the Unit Circle                     Functions on the Domain of Shapes

Meeting Up – on the road with red & blue      Modeling & formulating

Monge's Theorem                               Functions on the Domain of Shapes

Monkey drop                                   Physics Nuggets

Monkey drop in 3 frames of reference          Physics Nuggets

Monkey drop: space time diagram               Physics Nuggets

Monte Carlo Pi                                Modeling & formulating

More about ladders                            Parameter Spaces


Morphing polynomials                          Families of functions

Multiplying & dividing uncertain measurements Number sense & Computation...

Museum of Mathematics Exhibit                 Families of functions


Museum of Mathematics Exhibit II              Families of functions

N

Napoleon’s Theorem                            Functions on the Domain of Shapes

Newton & Aristotle: two ideas...              Physics Nuggets

NLAW - a game of kinematics                   Physics Nuggets

Normal distribution & cumulative probability  Physics Nuggets

O

One Quad = Four Triangles                     Functions on the Domain of Shapes

One Million Dollars                           Number sense & Computation...

Operations on Functions                       Function as Object

Operations on Functions - II                  Function as Object

Optimally Locating Public Services            Functions on the Domain of Shapes

                                              Modeling & formulating

Ordering Fractions                            Number sense & Computation...

Orthogonal Circles                            Functions on the Domain of Shapes


Overlapping Right Triangles                   Functions on the Domain of Shapes

P

Parallelogram Partition                       Functions on the Domain of Shapes

Parallelogram space                           Parameter Spaces

Parametric Polygon Explorer                   Parameter Spaces

Parametric Polygon Synthesizer                Parameter Spaces

Parabolas between parabolas                          Families of functions


Pascal's Theorem                              Functions on the Domain of Shapes

Peaucellier-Lipkin Linkage                    Functions on the Domain of Shapes

Pebble stuck in a wheel                       Physics Nuggets

Pebble stuck in a wheel - revisited           Physics Nuggets

                                              Parameter Spaces

Petals - a polar exploration                  Families of functions


Pi = 4 ?                                      Families of functions

                                              Functions on the Domain of Shapes

Place Value Decomposition                     Number sense & Computation...

Place Value - Decomposing Multiplication      Number sense & Computation...

Planetary Orbits in Two Frames                Modeling & formulating

                                              Physics Nuggets

Plato's Dice                                  Number sense & Computation...

                                              Probability

Playing with blocks                           Functions on the Domain of Shapes


Point in a Circle                             Functions on the Domain of Shapes

Point in an Equilateral Triangle              Functions on the Domain of Shapes

Point in an Equilateral Triangle - revisited  Functions on the Domain of Shapes

                                              Probability

Point in a Regular Pentagon                   Functions on the Domain of Shapes

Point in a Square                             Functions on the Domain of Shapes

Polya and the 3 circles                       Functions on the Domain of Shapes

Polya's Triangle Space                        Parameter Spaces

Polygon Explorer                              Functions on the Domain of Shapes


Polygonal pancakes                            Functions on the Domain of Shapes

                                              Modeling & formulating

Polygons in polygons                          Functions on the Domain of Shapes

Polygon Synthesizer                           Functions on the Domain of Shapes

                                              Modeling & formulating

Polygonal Numbers                             Modeling & formulating


Polygonal Trigonometric Functions             Families of functions


Power drill - estimating products             Number sense & Computation...


Power drill - estimating sums                 Number sense & Computation...


Power drill - exploring factoring & FOIL      Number sense & Computation...

Powers of Complex Numbers                     Families of functions

                                              Parameter Spaces

Power to the Base                             Number sense & Computation...


Primal Problem Generator                      Number sense & Computation...


p R I m E !                                  Number sense & Computation...

“…Princess and the Key”                       Modeling & formulating

                                              Physics Nuggets

Projectile in Parameter Space                 Physics Nuggets

                                              Parameter Spaces

Projectile with Air Resistance                Modeling & formulating

                                              Physics Nuggets

Projecting Quadrilaterals                     Functions on the Domain of Shapes

Push Me - Pull You                            Physics Nuggets

Q

Quad in a Quad                                Functions on the Domain of Shapes

Quadratic Inequalities Solved w/ Graphs &...  Equations & Inequalities as…

Quadratic Parameter Plane                     Parameter Spaces

Quadrilateral Factory ?                       Functions on the Domain of Shapes

Quadrilateral Invariant                       Functions on the Domain of Shapes

Quadrature of the Lune                        Functions on the Domain of Shapes

Quadrature of the Rectangle                   Functions on the Domain of Shapes

Quadrature of the Triangle                    Functions on the Domain of Shapes

R

Radii ?                                       Functions on the Domain of Shapes

Rain gutter                                   Modeling & formulating


Rate of Change - constant or accelerating     Function as Object

Rational Functions & Asymptotic Behavior      Function as Object

Rational Numbers & Equivalent Fractions       Parameter Spaces

Real & Complex roots of Quadratic functions   Function as Object

Recovering from a long lunch                  Modeling & formulating

Rectangles                                    Parameter Spaces

Rectangle space – width/height plane          Parameter Spaces

Rectangle space – area/perimeter plane        Parameter Spaces

Rectangularity of Parallelograms              Modeling & formulating

Regular Hexagon in a cube                     Functions on the Domain of Shapes

Relations that Function                       Function as Object

Rescue at Sea from an Elliptical Island       Functions on the Domain of Shapes

Reasoning about rates - Overlapping squ       Functions on the Domain of Shapes


Reasoning about rates - Overlapping cubes     Functions on the Domain of Shapes

Reasoning about rates - Overlapping circles   Functions on the Domain of Shapes

Reasoning about rates - Yellow bowties        Functions on the Domain of Shapes

Reasoning about rates - Yellow bowties II     Functions on the Domain of Shapes

Rhomboidicity of Kites                        Modeling & formulating

Rolling Disc Illusion                         Functions on the Domain of Shapes

Rolling a line in 3D...                       Functions on the Domain of Shapes


Roots & Asymptotes of Polynomials             Function as Object

Rotating Squares: an algebraic perspective    Functions on the Domain of Shapes

Rotating Squares: a geometric perspective     Functions on the Domain of Shapes

Round trips in maths; Non-invertable ops...   Function as Object

S

Sales Optimizer                               Modeling & formulating

Scaling the volume of a cone                  Functions on the Domain of Shapes

Scaling the surface area of a cone            Functions on the Domain of Shapes

See-Saw - multiplying signed numbers          Number sense & Computation...

'Semi-graphical' solution of linear eqns.     Equations & Inequalities as…

Seven Functions on a Triangle                 Functions on the Domain of Shapes

Ship Rendezvous                               Physics Nuggets
                                              Modeling & formulating

Shortest ladder                               Modeling & formulating


Side Parameter Space for Rectangles           Parameter Spaces

Single rotation replaces a rotation &...      Functions on the Domain of Shapes

Sir Isaac's Cars                              Physics Nuggets

Sir Isaac's Slalom                            Physics Nuggets

“…Sliding Ladder Problem”                     Modeling & formulating

                                              Physics Nuggets

Smoothness                                    Modeling & formulating

Solving Linear Equations & Inequalities..     Equations & Inequalities as…

Solving Quadratics Equations Graphically &... Equations & Inequalities as…


Spheres & shells, Circles & rings             Functions on the Domain of Shapes

Spinners as "Super-dice"                      Number sense & Computation...

                                              Probability

Spirals                                       Families of functions

Square in a Triangle                          Functions on the Domain of Shapes

Square in a Regular Tetrahedron               Functions on the Domain of Shapes

Squareness of Parallelograms                  Modeling & formulating

Squareness of Rectangles                      Modeling & formulating

Squareness of Rhombuses                       Modeling & Formulating

Squareness of Rectangles - revisited          Modeling & formulating

Squaring’ the circle                          Families of functions

Starting wave at a stop light                 Physics nuggets

Steepness - a road up a mountain              Modeling & Formulating

                                              Functions on the Domain of Shapes

Steepness - another  road up a mountain       Modeling & Formulating

                                              Functions on the Domain of Shapes

Students define a median                      Functions on the Domain of Shapes

Sum of Circle Areas                           Modeling & formulating

Sum of Polygonal Areas                        Modeling & formulating

                                              Functions on the Domain of Shapes

Sum of two reflections                        Functions on the Domain of Shapes

T

The ABC's of QR                               Parameter Spaces

Taking Sides                                  Functions on the Domain of Shapes

The 1089 Puzzle                               Number Sense & Computation...

The Array Model of Multiplication             Number Sense & Computation...

The Game of Arrows - adding signed numbers    Number sense & Computation...

The Kite & The Lemniscate                     Functions on the Domain of Shapes

The Locus of the Vertex                       Families of functions


The Polynomial Constructor                    Families of functions

The Roots of Unity                            Parameter Spaces

The Repentant Reader                          Modeling & formulating

The Repentant Reader - revisited              Modeling & formulating

The Parallelogram Factory                     Functions on the Domain of Shapes

The Secret Life of Triangle Medians...        Functions on the Domain of Shapes

The Three Roots of a Cubic Function           Function as Object

The Two faces of Z                            Parameter Spaces


There are planes & there are planes           Parameter Spaces


Three angles                                  Functions on the Domain of Shapes

Three Points on a Circle                      Parameter Spaces

                                              Probability

                                              Imagine…

Three Similar Triangles                       Functions on the Domain of Shapes

Three Tangent Circles                         Functions on the Domain of Shapes

Three Mutually Tangent Circles                Functions on the Domain of Shapes

Three 'nearSQUARES'                           Functions on the Domain of Shapes

Three Orthogonal Circles on a Triangle        Functions on the Domain of Shapes

Tic-Tact-Toe in 3D and 4D                     Imagine…


Tiling a Rectangle with Square Tiles          Number sense & Computation...

Town separation by road & crow                Functions on the Domain of Shapes

Transformations on Functions                  Function as Object


Translating f(x) to the right by A...         Function as Object


Travel Optimizer                              Modeling & formulating

Triangle on 3 parallel lines                  Functions on the Domain of Shapes

Triangle on 3 concentric circles              Functions on the Domain of Shapes

Two Analogous Problems                        Physics Nuggets


Two clocks in k/n time                        Physics Nuggets

Two dimensional oscillatory motion in...      Physics nuggets


Two motions - One Path in Space               Physics nuggets


Two Napkin Rings                              Functions on the Domain of Shapes

                                              Modeling & formulating

Two lap average                               Modeling & formulating

Two lap average - revisited                   Modeling & formulating

Two lap average for Teachers                  Modeling & formulating

Two metaphors - one model                     Modeling & formulating

Two motions - One Path in Space               Physics nuggets

                                              Parameter Spaces

                                              Modeling & formulating

Two Planets & A Sun                           Modeling & formulating

Two rectangles in a square                    Functions on the Domain of Shapes

Two rectangles in a square II                 Functions on the Domain of Shapes

Two trains and a fly                          Physics nuggets

Turning sine into cosine                      Families of functions

U

UNsolve 2 variable Linear Equations...        Equations & Inequalities as…

UNsolve 2 variable Quadratic Equations...     Equations & Inequalities as…

UNsolving Linear Equations & Inequalities     Equations & Inequalities as…

UNsolving Linear Equations - Two views        Equations & Inequalities as…

UNsolving Quadratic Equations & Inequalities  Equations & Inequalities as…

UNsolving Cubic Equations                     Equations & Inequalities as…

V

v = dx/dt                                     Modeling & formulating

                                              Physics Nuggets

W

Was Pythagoras wrong?                         Families of functions

Was Pythagoras wrong? - related heresies      Families of functions                                                                         Functions on the Domain of Shapes

Weigh to go !                                 Physics nuggets

                                              Modeling & Formulating 

...when x is not an integer                   Families of functions

When is AB equal to BA?                       Functions on the Domain of Shapes

Windscreen                                    Functions on the Domain of Shapes

Word Problem Duo - Mass,Volume,Density        Modeling & formulating

Word Problem Duo - Distance,Time,Rate        
Modeling & formulating

Why is -2 x -3 equal to +6 ?                  Number Sense & Computation...

Why Radians?                                  Functions on the Domain of Shapes

Y

Yaglom's Road                                 Functions on the Domain of Shapes

Yin Yang Yin                                  Functions on the Domain of Shapes


Judah L. Schwartz