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Subtraction within 20 - Worksheet 9 - 1st Grade

Hard

Subtract with minuends up to 20 (Hard)

30 problems · 10-15 minutes · Skills: subtraction, mental math

About This Worksheet

This hard-level worksheet contains 30 problems designed for 1st Grade students practicing subtraction within 20. Hard worksheets feature challenging problems including multi-step questions, missing values, and real-world applications to push students further.

Subtraction across ten is a key milestone. The strategies learned here — like breaking apart numbers — apply to subtracting much larger numbers.

How to Solve: Worked Example

Example Problem: 18 − ___ = 7
Solution Steps:
  1. Think: 18 minus what equals 7?
  2. Subtract: 18 − 7 = 11.
  3. Check: 18 − 11 = 7. Correct!
Answer: 11
Tip: Turn a missing subtrahend into a subtraction: total − result = missing number.
1
Start at 18, jump back 6 = ___
2
20 - 9 =
3
Start at 15, jump back 11 = ___
4
19 - 17 =
5
14 - 8 =
6
Start at 14, jump back 11 = ___
7
14 - 7 =
8
15 - ___ = 4
9
19 - ___ = 12
10
Start at 18, jump back 6 = ___
11
19 - ___ = 7
12
Start at 16, jump back 12 = ___
13
19 - 10 =
14
18 - 10 =
15
Start at 14, jump back 10 = ___
16
Start at 17, jump back 10 = ___
17
16 - 10 =
18
20 - 18 =
19
16 - 13 =
20
17 - 7 =
21
Start at 14, jump back 10 = ___
22
13 - ___ = 8
23
16 - 13 =
24
Start at 18, jump back 8 = ___
25
Start at 14, jump back 6 = ___
26
15 - ___ = 6
27
15 - 11 =
28
Start at 18, jump back 7 = ___
29
19 - 9 =
30
Start at 14, jump back 8 = ___

Answer Key

1. 122. 113. 44. 25. 66. 37. 78. 119. 710. 1211. 1212. 413. 914. 815. 416. 717. 618. 219. 320. 1021. 422. 523. 324. 1025. 826. 927. 428. 1129. 1030. 6

Frequently Asked Questions

How do I download this subtraction within 20 - worksheet 9 worksheet?

Click the "Download PDF / Print" button at the top of the worksheet. You can save it as a PDF or print it directly. The answer key will be on a separate page.

How do I find worksheets at different difficulty levels?

Each subtopic has 10 worksheets: Worksheets 1-3 are Easy, 4-7 are Medium, and 8-10 are Hard. Start with Easy worksheets to build confidence, then progress to harder ones.

How many problems are on this worksheet?

This worksheet contains 30 problems. It typically takes 10-15 minutes to complete. An answer key with all solutions is included.