Overview

Grade 1 Math

B2. Operations

9. B2.2 Math Facts

9.2 Subtracting with digits up to 20

Subtracting with Digits up to 20

Learn how to subtract numbers up to 20 confidently using counting back, number lines, and subtraction fact strategies.

What You'll Learn

Recognize what the subtraction sign \( - \) means when taking one quantity away from another.

Apply the counting back strategy to solve problems like \( 17 - 5 = 12 \).

Use a number line to model subtraction by moving left from the starting number.

Recall subtraction facts up to 20 to solve problems quickly without counting every time.

Check answers by adding the difference back to the number subtracted, since \( 12 + 5 = 17 \).

What You'll Practice

Solving subtraction problems with numbers from 0 to 20

Computing differences with single-digit and teen numbers

Practicing mental subtraction strategies

Why This Matters

Subtracting with digits up to 20 is a fundamental skill you'll use every day, from counting change to solving more complex math problems. Mastering these facts builds the foundation for multi-digit subtraction, algebra, and real-world problem solving.

This Unit Includes

Practice exercises

Learning resources

Skills

Subtraction

Basic Operations

Number Sense

Mental Math

Arithmetic Facts

ON Curriculum Aligned