Estimation to check answers to calculations
Use estimation to check answers to calculations and determine, in the context of a problem, an appropriate degree of accuracy
Lesson
Set out your lesson
Estimate products and quotients to detect unreasonable answers. Decide when an estimate is enough and when an exact answer is needed.
Before teaching
Use this short check, then start teaching.
Ask for 6 × 4 (24), 60 × 40 (2,400), and 240 ÷ 6 (40). Ask for 487 rounded to 100 (500). Multiplication, division and place-value readiness are local checks, not added canonical edges. If they need support, teach them separately before using this lesson as independent practice.
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Estimate products and quotients to detect unreasonable answers. Decide when an estimate is enough and when an exact answer is needed.
Estimate products and quotients to detect unreasonable answers. Decide when an estimate is enough and when an exact answer is needed.
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Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
BBC Bitesize · Practice link — not the full lesson
KS2 Maths
Before you open · source notes
KS2 Maths supports Estimation to check answers to calculations. An adult previews and guides; this is a learning page, not a scored quiz.
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Source, access and review notes
Public BBC Bitesize page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.
BBC Bitesize. “KS2 Maths.” External page; Gakuva does not copy, host, embed, or redistribute materials.
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Check understanding
- Estimate 487 × 23 by rounding to 500 × 20 and use this to check a calculated answer
- Determine whether an exact answer or an estimate is more appropriate in a given context
- Spot an unreasonable answer by comparing with a quick mental estimate
“Before your child works out a large multiplication or division, can they estimate what the answer should be roughly — and then check whether their final answer is in the right ballpark?”
Curriculum record
- Type
- Meta
- Subject
- Mathematics
- Domain
- Multiplication & Division
- Age range
- Ages 10–12
Standards