Operations to 100
- Add and subtract whole numbers to 100, including regrouping (trading ten ones for a ten).
- Use strategies: counting on, making tens, and using known facts.
- Meet multiplication as equal groups and repeated addition — 3 groups of 4 is 4 + 4 + 4.
- Arrange objects in arrays (rows and columns) to see products.
Estimating first (*"about how many?"*) helps you judge whether your exact answer makes sense.