MathematicsNumber Representation & Place ValueAges 7–9

10 or 100 More or Less

Find 10 or 100 more or less than a given number up to 1000

Lesson

Set out your lesson

Add or subtract tens and hundreds, including regrouping boundaries.

Before teaching

Use this short check, then start teaching.

Activity

Inferred, not a taxonomy edge: learner can access the supplied prompt with agreed support and can explain or mark a response. If earlier skills are unfamiliar, use the prerequisite topic for teaching; an authored prerequisite is not proof this learner is ready.

Printer, credit, and teaching notes

Sequence

Keep the two adult-only cards off the learner screen. Have a pencil and scrap paper if useful; oral pointing/typing/AAC can replace handwriting unless spelling or composition is the target. No printing, cutting, account or purchase is required.
Open Show first, read the explanation together, and pause to check the central idea. Then do Guided Try together.
For Try, close earlier models and the adult keys unless the task explicitly supplies a reference. Record any hints, read-aloud help or model reopening; do not call supported work independent.
Use only the active learner card. Keep the private key closed until an attempt is recorded. Stop or take a break on request; practical claims stay not observed unless actually done.

No Printer

Use on screen; read aloud or recreate a tactile model only with declared support. No printer or purchased kit.

Privacy

Never display adult keys or dictation spellings with a learner task; no family financial, identity or conflict disclosure.

Use the complete materials on screen or print only the current sheet. Keep adult guidance out of learner view.

Next: Show

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Entire curriculum

1858 concepts · 9 subjects

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Teaching approaches

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1 approach

Selected Default Gakuva

Add or subtract tens and hundreds, including regrouping boundaries.

Family records and proof options

Keep a record of your learning

Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.

View learner plans ($12/mo per learner) See sample family archive

Learning resources

Extra practice links — they do not replace Gakuva’s teaching approach.

Illustrative Mathematics · Practice link — not the full lesson

Choral Counting

Open practice(new tab)

Before you open · source notes

A class count records jumps of 10 or 100 with base-ten thinking. Use it for 10 or 100 more or less, not every skip-count song.

Free, no sign-in. A teacher solution is on the same page, so use the student view with your child.

Before you open

Ask what number is 10 or 100 more than a starting number on the recorded count.

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. “Choral Counting.” 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

Given a three-digit number, state what is 10 more and 10 less
Given a three-digit number, state what is 100 more and 100 less
Explain the strategy using place-value understanding (e.g. only the tens/hundreds digit changes)

“Can your child quickly work out '10 more than 342' or '100 less than 875' in their head — knowing which digit changes and which stays the same?”

Curriculum record

Type: Procedural
Subject: Mathematics
Domain: Number Representation & Place Value
Age range: Ages 7–9

Standards

ccss-math:2.NBT.8the-ontario-curriculum-mathematics-2020:ON-MATH-2020-G3-B2.3the-ontario-curriculum-mathematics-2020:ON-MATH-2020-G3-C1.4uk-nc-2013:Ma/KS2/Y3/NPV/1