Adding and subtracting (age 7+)
Add and subtract numbers with up to three digits using formal written methods of columnar addition and subtraction
Entire curriculum
1858 concepts · 9 subjects
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Teaching approaches
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1 approach
Use aligned written columns, equal-value exchanges, and inverse checks.
Use aligned written columns, equal-value exchanges, and inverse checks.
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Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
Illustrative Mathematics · Practice link — not the full lesson
Boys and Girls, Variation 2
Before you open · source notes
A second boys-and-girls story builds adding and subtracting with unknowns. Not every decimal calculation.
Free, no sign-in. A teacher solution is on the same page, so use the student view with your child.
Before you openAsk the learner to name the unknown and solve with addition or subtraction.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public Illustrative Mathematics task page. The .html address responds HTTP 308 to this URL. An anonymous GET of this URL on 2026-11-12 returned HTTP 200 with no login or payment prompt. Where a teacher solution is present, it is on the same page as the student task; this check did not find a separate locked student view. An adult can use the student view section and should not read a solution aloud. Advertising was not observed in the fetched HTML text; that is not a browser, device, or ad-free guarantee. This is a paper or discussion task, not an automatically marked interactive game. Opening the link does not save practice or assess mastery. Diagrams on the page use missing or filename-only alt text, so they are not an accessible image equivalent. Accessibility still depends on an adult describing the picture.
Illustrative Mathematics. “Boys and Girls, Variation 2.” Licensed CC BY-NC-SA 4.0. External task; Gakuva does not copy, host, embed, or redistribute it.
CC BY-NC-SA 4.0 — link only
Check understanding
- Set out a columnar addition correctly with digits aligned by place value
- Carry out columnar subtraction with exchange (borrowing) when needed
- Check the answer using the inverse operation or estimation
“Can your child set out a sum like '347 + 265' or '512 − 278' in columns and work through it step by step, carrying or borrowing where needed?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Addition & Subtraction
- Age range
- Ages 7–9
Standards