Math in My Head: Mental Addition and Subtraction Strategies

About This Resource

A free Grade 2 math worksheet on mental strategies: make ten (8 + 5 = 8 + 2 + 3), near doubles (12 + 13), adding 9 or 11 by adjusting (34 + 9 = 34 + 10 − 1) and adding or subtracting tens first. Children practice each strategy, choose the best one and explain their thinking. Includes a timed lesson plan, a six-activity worksheet, an editable Word version and answer key.

Overview

Children learn quick ways to add and subtract in their heads instead of counting on by ones. To make ten, they split a number so one part fills up to ten (8 + 5 = 8 + 2 + 3 = 13). With near doubles, they use a double they know (12 + 13 = 12 + 12 + 1). To add 9, they add 10 and take away 1; to add 11, they add 10 and add 1 more. To add two-digit numbers, they add the tens first and then the ones. Children practice each strategy, decide which one works best for a calculation and explain their thinking to a partner.

Resource Details

Subject: Math
Topic: Mental Addition and Subtraction Strategies
Category: Addition & Subtraction
File Type: PDF
File Size: 189.4 KB
Published: 13 Nov 2026
Downloads: 0

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Grade 2 math (ages 7–8) 45 minutes Mental math number bonds place value reasoning

Student Task

Write 8 + 5 on the board. Ask: "How can you solve it without counting on your fingers?" Share ideas.
Model each strategy, then do activities 1 and 2 together.
Children complete activities 3 to 6. Answers are in the answer key.

Classroom Use

Strategy sort: children sort calculation cards by the strategy they would use.
Ten frame race: children show 8 + 5 on ten frames, moving two counters to fill the frame.
Explain it: one child solves a calculation aloud while a partner names the strategy.

Differentiation

Support: use ten frames and number lines and focus on make ten and near doubles. Challenge: children use the strategies for subtraction (52 − 9 = 52 − 10 + 1) and invent their own examples.

Answer Key & Assessment

Activities 1 to 5 check each strategy (answer key included). Activity 6 shows whether children can explain their choice.

Learning Objectives

Use make ten, near doubles and adjusting (adding 9 or 11) to add mentally.
Add and subtract tens first, then ones.
Choose an efficient strategy and explain it.

Teacher Tips

Children need to know number bonds to 10 and doubles to 10 + 10 before these strategies feel easy. Accept any efficient strategy a child can explain, and ask: Is there a quicker way?

What's Included

6-page printable PDF lesson pack: teacher lesson plan with timings, materials and differentiation
Key vocabulary list (6 words with meanings and examples)
Student worksheet (6 activities)
Editable Word version of the worksheet
Complete answer key (also as a separate PDF)

Additional Files

Make a Ten and Carry: Adding Two-Digit Numbers with Regrouping

Adding Two-Digit Numbers with Regrouping

A complete Grade 2 math lesson pack on adding two-digit numbers with regrouping: base-ten ...

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