100 guided animations · 10 topic units · Free to explore
Make a prediction, change a value, and explain the result. Work through each unit in order or choose the topic you want to understand today. Every investigation has controls, a worked explanation, and a question to test your reasoning.
Your collection at a glance
Read hundreds tens and ones
Investigations 1–10
Add through a new ten
Investigations 11–20
Subtract from a larger collection
Investigations 21–30
Land on repeated equal jumps
Investigations 31–40
Rows make repeated addition visible
Investigations 41–50
Deal equal shares and keep leftovers
Investigations 51–60
Repeat equal measuring units
Investigations 61–70
Trace all four boundary lengths
Investigations 71–80
Read minutes around the clock
Investigations 81–90
Compare counts on a common scale
Investigations 91–100
Related investigations use the same mathematical model with different questions and starting values. Reset restores the values used in that investigation’s worked answer. Read its assumptions before applying a model to a new situation.
100 animations · Showing 1–20
Grade 2 · Place value
Read hundreds tens and ones · Investigation 1 of 100
An inventory at a board-game club records 1 hundreds, 0 tens, and 0 ones of cards. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 2 of 100
An inventory at a community garden records 2 hundreds, 3 tens, and 7 ones of flowerpots. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 3 of 100
An inventory at a school fair records 3 hundreds, 6 tens, and 4 ones of tickets. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 4 of 100
An inventory at a bakery records 4 hundreds, 9 tens, and 1 ones of rolls. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 5 of 100
An inventory at a recycling station records 5 hundreds, 2 tens, and 8 ones of clean cans. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 6 of 100
An inventory at a science museum records 6 hundreds, 5 tens, and 5 ones of badges. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 7 of 100
An inventory at a swimming meet records 7 hundreds, 8 tens, and 2 ones of ribbons. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 8 of 100
An inventory at a craft workshop records 8 hundreds, 1 tens, and 9 ones of beads. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 9 of 100
An inventory at a transport model records 1 hundreds, 4 tens, and 6 ones of passenger counters. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Place value
Read hundreds tens and ones · Investigation 10 of 100
An inventory at a nature trail records 2 hundreds, 7 tens, and 3 ones of trail markers. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 11 of 100
At a board-game club, a first group contains 18 cards and another group brings 7 cards. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 12 of 100
At a community garden, a first group contains 25 flowerpots and another group brings 10 flowerpots. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 13 of 100
At a school fair, a first group contains 32 tickets and another group brings 13 tickets. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 14 of 100
At a bakery, a first group contains 39 rolls and another group brings 16 rolls. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 15 of 100
At a recycling station, a first group contains 46 clean cans and another group brings 19 clean cans. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 16 of 100
At a science museum, a first group contains 53 badges and another group brings 22 badges. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 17 of 100
At a swimming meet, a first group contains 60 ribbons and another group brings 25 ribbons. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 18 of 100
At a craft workshop, a first group contains 67 beads and another group brings 28 beads. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 19 of 100
At a transport model, a first group contains 74 passenger counters and another group brings 31 passenger counters. Change the controls and explain what the animation reveals.
Explore animationGrade 2 · Addition
Add through a new ten · Investigation 20 of 100
At a nature trail, a first group contains 81 trail markers and another group brings 34 trail markers. Change the controls and explain what the animation reveals.
Explore animation