Subtracting multiples of 10
Subtract multiples of 10 (10–90) from multiples of 10 using place value strategies
Lesson
Set out your lesson
“Subtracting multiples of 10 means taking a multiple of ten away from another multiple of ten by thinking in tens, not by counting back by ones. 70 − 30 is seven tens minus three tens, which leaves four tens (40). We will build tens groups, remove tens, then try a mental answer with a quick check.”
Bring to the table
- About 90 large counters grouped in tens, or drawn tens sticks on paper (parent keeps tiny pieces away from mouths)
- Paper and pencil
Extra for the adult
Worked example. 70 − 30 = 40 because seven tens minus three tens leaves four tens. 90 − 50 = 40 the same way. Both start and result stay multiples of ten when you subtract a multiple of ten from a multiple of ten.
Optional challenge. For Subtracting multiples of 10, solve 100 − 40 and explain the tens change, then invent one short “tens left” story using page numbers or packs of ten. Optional: relate 80 − 30 to “eight tens take three tens.”
What to notice. Keep one parent note: equations tried; answers; whether tens groups were used; the child’s words about tens; support used. A photo of tens piles alone cannot record the place-value talk. This session samples a few pairs, not fluency for every case.
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Teaching approaches
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1 approach
Subtracting multiples of 10 means taking a multiple of ten away from another multiple of ten by thinking in tens, not by counting back by ones. 70 − 30 is seven tens minus three tens, which leaves four tens (40). We will build tens groups, remove tens, then try a mental answer with a quick check.
Spend about 12 minutes subtracting multiples of 10 from multiples of 10 with tens groups or drawings, writing the equations, then answering two mental items that stay on the tens.
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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
One, Ten, and One Hundred More and Less
Before you open · source notes
Ten more and ten less practice supports subtracting multiples of 10. Not every three-digit subtraction algorithm.
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 say a number that is ten less than a given number and explain the digit change.
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. “One, Ten, and One Hundred More and Less.” 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
- Calculate 70 − 30 = 40
- Use base-ten blocks to show 80 − 50 = 30
- Explain that subtracting tens is like subtracting the tens digits
“Can your child quickly work out '80 − 50' or '70 − 40' in their head by thinking about how many tens are left?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Addition & Subtraction
- Age range
- Ages 6–7
Standards