Adding and subtracting decimals
Add and subtract decimals to hundredths using strategies based on place value, properties of operations, and the relationship between addition and subtraction; relate strategies to written methods and explain reasoning
Lesson
Set out your lesson
“Adding and subtracting decimals means practising the idea at the table with counters or paper models and one clear check. We will demo once, then your child tries.”
Bring to the table
- Place-value grid (ones / tenths)
- Pencil
Extra for the adult
Worked example. Three tenths on the grid is 0.3.
Optional challenge. For Adding and subtracting decimals, add one harder example after success.
What to notice. Keep one parent note: examples tried; results; support used. This session samples Adding and subtracting decimals, not mastery.
Share and support
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.
Practice this concept
Start practiceAdding and subtracting decimals practice
Practice key ideas from Adding and subtracting decimals.
Free · no login · no ads · Practice answers and completion are not saved. Parent observation remains the lesson record.
Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
Illustrative Mathematics · Practice link — not the full lesson
Are these equivalent to 9.52?
Before you open · source notes
Decimal equivalents support careful adding and subtracting with tenths and hundredths. Not every fraction 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 decide whether two decimal writings equal 9.52 and say how they know.
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. “Are these equivalent to 9.52?.” 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
- Correctly compute 3.45 + 2.78 and explain regrouping across decimal places
- Use a number line or base-ten blocks to model 5.03 − 2.67
- Explain why the standard algorithm works for decimal addition by connecting to place-value understanding
“Can your child add or subtract decimal amounts like '4.73 + 2.68' or '10.00 − 3.47', lining up the decimal points and working through the columns correctly?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Addition & Subtraction
- Age range
- Ages 9–13
Standards