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 1st Class and 2nd Class.
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.