Addition and subtraction
The algorithm is regrouping; the thinking is compensation and bar models for comparison. Students add and subtract multi-digit numbers with several regroupings (including across zeros), estimate to check, and solve two-step comparison problems from a bar model.
Specification · for a parent or teacher
- multi-digit-add-sub
- Advanced Math 4 · Unit 2
- Foundations
- 1 of 4 — Grade 4 fluency. One idea, one step.
- 3 items
Students can
add and subtract multi-digit numbers with several regroupings, including zeros; estimate to check; solve two-step comparison problems with a bar model.
Ready when
they can write a bar model for “A is 1,250 more than B; together they are 8,000” and find both amounts.
Watch for
subtracting across zeros (5003 − 278); treating “difference” as the leftover bar rather than the comparison.