Mental and written addition and subtraction
Solve addition and subtraction problems using mental and written methods, including problems involving numbers, quantities, and measures
Lesson
Set out your lesson
“Mental and written addition and subtraction means solving +/− problems with both a quick mental strategy and a written record—covering number facts, quantities of objects, and simple measure stories. We will solve one of each kind, write the equation, then check a fresh mixed pair.”
Bring to the table
- About 30 large counters or household objects for quantities (parent keeps tiny pieces away from mouths)
- Paper and pencil for written methods
- Optional: a kitchen measure story (cups of water, spoonfuls) without sharp tools
Extra for the adult
Worked example. 9 + 6 = 15 (mental make-ten, then written). 18 − 7 = 11 with counters matching the written equation. A spoonful story uses the same +/− methods with a measure quantity.
Optional challenge. For Mental and written addition and subtraction, invent one kitchen measure story and one object story; solve each mentally first, then write both equations. Optional: explain when writing helped catch a mental slip.
What to notice. Keep one parent note: problems tried; mental vs written methods; answers; support used. A photo of counters alone does not show the method choice. This session samples a few items, not mastery of all +/− problems.
Share and support
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Teaching approaches
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1 approach
Mental and written addition and subtraction means solving +/− problems with both a quick mental strategy and a written record—covering number facts, quantities of objects, and simple measure stories. We will solve one of each kind, write the equation, then check a fresh mixed pair.
Spend about 12 minutes solving addition and subtraction problems mentally and on paper—numbers, object quantities, and a short measure story—then checking two fresh items.
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.
Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
Illustrative Mathematics · Practice link — not the full lesson
Sharing Markers
Before you open · source notes
A marker-sharing story supports mental or written addition and subtraction. Not every regrouping 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 show one mental and one written way to find how many markers.
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. “Sharing Markers.” 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
- Solve a two-step problem: 'I had 35p, spent 12p, then found 5p. How much now?'
- Choose an appropriate method (mental or written) for a given problem
- Solve problems involving measures, e.g. 'a ribbon is 45cm, I cut off 18cm'
“If your child is given a problem involving lengths, weights, or prices, can they decide whether to add or subtract and carry out the calculation correctly?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Addition & Subtraction
- Age range
- Ages 6–7
Standards