Add and subtract to one hundred

Use tens and ones or a known relationship to add and subtract within one hundred.

1. Show a tens-and-ones drawing. Regroup only when the learner can explain that ten ones and one ten have the same value.
2. Work through the example. Explain how its evidence supports the answer.
3. Try a new question; use the explanation to check your thinking.

Try it together

Try a question with a partner. Before choosing, explain your idea; after choosing, compare it with the explanation.

Show a tens-and-ones drawing. Regroup only when the learner can explain that ten ones and one ten have the same value.