Add and subtract within 100
Free practice for add and subtract within 100. It loads instantly, there is nothing to sign up for, and it stops after eight questions.
What this skill is
Multi-digit arithmetic, done with understanding rather than as a memorised ritual. Estimation first catches most of the errors before they happen.
Three ways to teach it at home
- Estimate first. Always.
- If they are regrouping mechanically, go back to base-ten blocks for two minutes. It is faster than three weeks of wrong answers.
- Write the steps out in words once, then let them work.
Where this sits in the ladder
Comes after
Opens next
This is the top of its strand.
Questions people actually ask
What grade is "add and subtract within 100"?
It sits in grade 2 in most sequences, and it is aligned to 2.NBT.B.5. In Ladderbug it opens once place value to 100 is solid — grade labels are a rough guide, and readiness is what actually matters.
Is this game free?
Yes. This page needs no account, no email and no card, and there are no advertisements. It saves progress in your own browser.
What mistakes should I watch for?
Takes the smaller digit from the larger one whatever the position. We probe for it deliberately by offering that exact wrong answer as a choice, and if a child picks it twice we go back to place value to 100 rather than repeating the same question.
This is one rung of 82.
Open the whole ladder — free