Adding two two-digit numbers
Add and subtract two two-digit numbers using concrete objects, pictorial representations, and mental methods
Lesson
Set out your lesson
“Adding two two-digit numbers means combining two numbers such as 24 + 35 with objects, a sketch, or a mental move—and the same toolkit for a related subtraction. We will add with tens and ones, show one subtraction, then check a fresh pair.”
Bring to the table
- Base-ten materials or large counters for tens and ones (parent keeps tiny pieces away from mouths)
- Paper and pencil for drawings and equations
Extra for the adult
Worked example. 24 + 35 → 2 tens + 3 tens and 4 ones + 5 ones → 5 tens 9 ones = 59. A sketch or mental “add tens, then ones” should match the concrete total.
Optional challenge. For Adding two two-digit numbers, solve 38 + 27 two ways (materials and mental) and one subtraction such as 65 − 32. Optional: explain when a sketch caught a mental slip.
What to notice. Keep one parent note: problems tried; methods (objects/sketch/mental); answers; support used. A photo of sticks alone does not show the method choice. This session samples a few items, not mastery of all two-digit ±.
Share and support
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Teaching approaches
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1 approach
Adding two two-digit numbers means combining two numbers such as 24 + 35 with objects, a sketch, or a mental move—and the same toolkit for a related subtraction. We will add with tens and ones, show one subtraction, then check a fresh pair.
Spend about 12 minutes adding and subtracting two two-digit numbers with concrete materials, a picture, and a mental check, then verifying a new pair.
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
Many Ways to do Addition 2
Before you open · source notes
Two-digit additions are solved with more than one place-value strategy. Use it for two-digit sums, not every column algorithm.
Free, no sign-in. A teacher solution is on the same page, so use the student view with your child.
Before you openAsk for two different ways to add the same two-digit pair. Showing two ways does not prove every written method.
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. “Many Ways to do Addition 2.” 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 34 + 27 using base-ten blocks or column addition
- Calculate 63 − 28 using a number line or partitioning
- Explain a strategy for adding or subtracting two two-digit numbers
“Can your child add or subtract two two-digit numbers — like '43 + 28' — using counters, a drawing, or working it out in their head?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Addition & Subtraction
- Age range
- Ages 3–8
Standards