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
Count a collection once
Investigations 1–10
Join two small groups
Investigations 11–20
Remove a part and recount
Investigations 21–30
Compare by making pairs
Investigations 31–40
See ten and the extra part
Investigations 41–50
A bundle of ten and loose ones
Investigations 51–60
Count forward from a starting point
Investigations 61–70
Align ends to compare lengths
Investigations 71–80
Share fairly between two or four
Investigations 81–90
Read three picture counts
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 1 · Number sense
Count a collection once · Investigation 1 of 100
At a school garden, 5 seedlings are arranged with up to 2 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 2 of 100
At a picnic table, 6 apples are arranged with up to 3 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 3 of 100
At an art station, 7 crayons are arranged with up to 4 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 4 of 100
At a construction corner, 8 blocks are arranged with up to 5 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 5 of 100
At a reading corner, 9 books are arranged with up to 2 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 6 of 100
At a pretend toy shop, 10 toy cars are arranged with up to 3 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 7 of 100
At a music classroom, 11 bells are arranged with up to 4 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 8 of 100
At a playground, 12 cones are arranged with up to 5 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 9 of 100
At a classroom aquarium display, 13 fish tokens are arranged with up to 2 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Number sense
Count a collection once · Investigation 10 of 100
At a weather chart, 14 sun stickers are arranged with up to 3 in each display row. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 11 of 100
At a school garden, a first group contains 0 seedlings and another group brings 10 seedlings. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 12 of 100
At a picnic table, a first group contains 1 apple and another group brings 9 apples. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 13 of 100
At an art station, a first group contains 2 crayons and another group brings 8 crayons. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 14 of 100
At a construction corner, a first group contains 3 blocks and another group brings 7 blocks. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 15 of 100
At a reading corner, a first group contains 4 books and another group brings 6 books. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 16 of 100
At a pretend toy shop, a first group contains 5 toy cars and another group brings 5 toy cars. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 17 of 100
At a music classroom, a first group contains 6 bells and another group brings 4 bells. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 18 of 100
At a playground, a first group contains 7 cones and another group brings 3 cones. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 19 of 100
At a classroom aquarium display, a first group contains 8 fish tokens and another group brings 2 fish tokens. Change the controls and explain what the animation reveals.
Explore animationGrade 1 · Addition
Join two small groups · Investigation 20 of 100
At a weather chart, a first group contains 9 sun stickers and another group brings 1 sun sticker. Change the controls and explain what the animation reveals.
Explore animation