Subtraction Within 20: Games, Strategies & Worksheet
Subtraction within 20 means taking away from numbers up to 20, like 15 − 7. Knowing the matching addition facts makes subtraction much quicker.
➖ Play the subtraction within 20 game 🖨️ Printable worksheet
Tricks that make it easier
- Think addition: 13 − 5 = ? because 5 + 8 = 13.
- Count back for small numbers, count up for numbers close together (12 − 9: count up 3).
- Bridge back through 10: 14 − 6 = 14 − 4 − 2 = 8.
Try these
- 9 − 0 =
Answer
9 - 18 − 8 =
Answer
10 - 14 − 2 =
Answer
12 - 19 − 5 =
Answer
14 - 14 − 6 =
Answer
8 - 11 − 10 =
Answer
1
Common mistakes
- Subtracting the smaller digit from the bigger one in each column (72 − 38 = 46).
- Counting the starting number when counting back.
- Not checking the answer by adding back.
A five-day practice plan
| Day | What to do (10 minutes) |
|---|---|
| Day 1 | Play Subtraction Sprint on this skill for 5–10 minutes. Read the explanation after every mistake. |
| Day 2 | Learn one trick from this page and use it out loud while you play. |
| Day 3 | Print the worksheet and try it without help. Mark it with the answer key together. |
| Day 4 | Play again and try to beat your personal best score or get three stars. |
| Day 5 | Mix it up: try the ⏱️ Timed test, or ask your child to explain the skill to you in their own words. |
Suits Class 1 and Class 2.
Frequently asked questions
What does subtraction within 20 mean?
It means subtracting with numbers up to 20, so the starting number is 20 or less.
How do I check a subtraction answer?
Add your answer to the number you took away. If you get back to the starting number, your answer is right.
Is there a printable worksheet?
Yes. The subtraction within 20 worksheet has 30 questions with an answer key.