Subtraction Within 20 Worksheet

Subtraction within 20 is a key skill that first and second graders need to master for long-term math success. This free printable worksheet provides focused practice with subtraction problems where the minuend is 20 or less, including challenging problems that cross the ten boundary such as 15 - 7 = 8, 13 - 6 = 7, and 18 - 9 = 9. These problems build on the foundation established by subtraction within 10 and prepare students for multi-digit subtraction with regrouping.

What Does This Worksheet Cover?

This worksheet includes a balanced mix of subtraction problems using numbers from 0 through 20. Students will encounter straightforward problems where no regrouping is needed (such as 17 - 4) alongside more demanding problems that require decomposing a teen number across the ten boundary (such as 14 - 8). Problems are presented in horizontal format, giving children practice reading and solving standard number sentences. The carefully sequenced difficulty helps students build confidence as they work through the page.

Why Subtraction Within 20 Matters

Subtraction is the inverse of addition, and understanding both operations together gives children a complete picture of how numbers relate to each other. Fluency with subtraction facts to 20 is essential for success with multi-digit subtraction, which requires mentally subtracting single-digit numbers during the regrouping process. Students who can quickly recall that 16 - 9 = 7 or that 20 - 13 = 7 will find later math topics like measurement, money, and word problems much more manageable. National math standards expect students to demonstrate fluency with these facts by the end of second grade.

How to Use This Worksheet

• Connect to addition: Remind your child that every subtraction fact has a related addition fact. If 8 + 5 = 13, then 13 - 5 = 8. This connection makes subtraction easier to understand.
• Use counting back: For problems like 15 - 3, teach your child to start at 15 and count back three numbers: 14, 13, 12.
• Break through ten: For harder problems like 14 - 6, show your child how to subtract to 10 first (14 - 4 = 10), then subtract the rest (10 - 2 = 8).
• Practice with manipulatives: Use blocks, coins, or small objects grouped into tens and ones to make the subtraction process visible and concrete.

Tips for Parents and Educators

If your child finds certain facts particularly difficult, create fact family triangles showing the relationship between three numbers (for example, 7, 8, and 15). Practice these related facts together: 7 + 8 = 15, 8 + 7 = 15, 15 - 7 = 8, and 15 - 8 = 7. Pair this worksheet with the addition within 20 worksheet to reinforce both operations simultaneously. Short daily sessions of five to ten minutes are far more effective than occasional longer practice.