THREE NUMBERS. MORE THAN ONE FACT.
Which equations belong together?
3 + 7 = 10. So 10 − 3 = 7. But a correct equation can still belong to a different family. Sort the facts and spot the impostors.
Try the free tool ↓Six untimed practice families. No sign-up, score pressure or download needed to play.
THE INTERACTIVE WORKSPACE
Choose every equation in the family.
Select all true addition or subtraction equations made from these three numbers. A true equation with a different number does not belong.
Moving between families keeps your selections and explanations while this page is open. Editing a correctly checked set removes it from the correct count until you check again. A revealed family stays marked as revealed. Restart or refresh clears everything.
USE IT IN REAL LIFE
A family is a relationship, not just a correct answer.
For 3, 7 and 10, the two parts join in either order: 3 + 7 = 10 and 7 + 3 = 10. Start with the whole and remove either part: 10 − 3 = 7 and 10 − 7 = 3.
Now compare 1 + 9 = 10. The arithmetic works, but it uses different parts. That makes it a true equation from another family.
Why does the doubles family look shorter?
For 6, 6 and 12, swapping the equal parts repeats the same equation. There are only two distinct equations here: 6 + 6 = 12 and 12 − 6 = 6. This activity does not count duplicates as extra facts.
Try a zero part
In the 0, 8, 8 family, adding zero leaves the whole unchanged. Subtracting the whole leaves zero. Read each equation aloud and point to the part that was joined or removed.
For a grown-up helping: ask “Which numbers are the parts?” before asking for the answer. Use ten counters or drawn dots if the symbols feel abstract. This is practice, not an assessment or a promise of learning gains.
THE NEXT STEP
Ready to make the numbers do something?
Number Beasts turns number bonds into a puzzle: launch a number, make ten, and plan where the leftover goes. The game includes handcrafted stages and a puzzle-building Workshop. Try the free app when you want to move from sorting facts to planning a shot.
Play free Number Beasts ↗The current App Store listing says free, no ads and no in-app purchases; offline play is included. iOS/iPadOS 18 or later. This sorting activity is a separate browser companion, not a reproduction of a game level.
Publisher disclosure: Honest Little Apps publishes Number Beasts and this companion. This is not an independent review. App details checked November 5, 2026.
Try an equal-expression puzzle
Find the missing addend to balance both sides. Play five original rounds and check each result.
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