Subtraction within 20 represents taking away, comparing two quantities, or finding an unknown part of a whole, with nonnegative differences from 0 through 20. Learners connect subtraction to addition, use related fact families, and reason with decomposing to make ten, counting back, and representations such as ten-frames, part–part–whole diagrams, and number lines; the scope excludes negative results, larger numbers, and formal multi-digit subtraction algorithms.
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- Learn “Subtract within 20” with a detailed explanation of the concept
- Master “Subtract within 20” with unlimited, free practice problems
- Download (or modify) a free worksheet on Subtract within 20 you can use at home or in class with practice problems that scaffold and explore “Subtract within 20” from different perspectives.
- Start working on adaptive units like “Picture Numbers - Addition and Subtraction” or “Picture Numbers - Subtraction Intro” that introduce, teach, or practice “Subtract within 20” to maximize your learning.
Detailed Explanation: Subtract within 20
Subtraction tells how many are left when some are taken away.
Example: Solve .
- Start with .
- Take away to get to :
- You still need to take away , because :
- So,
You can check with addition: . Therefore, the answer is .
Learn by doing: Subtract within 20
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Practice:
Picture Numbers - Subtracting - Picture and Instruction to Number (Within 20)
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Download/Modify Free Grade 1 'Subtract within 20' Worksheet
Print this free 'Subtract within 20' worksheet to practice this skill away from the computer. Click 'Modify' to easily customize this worksheet to your exact needs.
This Worksheet Includes:
- Picture Numbers - Subtracting - Picture and Instruction to Number (Within 20)
- Ten Groups - Subtract, Without Borrow, Less than 20
- Subtraction - Whole Number - Within 20
- Subtraction - Missing Value, Within 20
- Subtraction - Whole Number - Within 10
- Subtraction - Whole Number 1 x 1
- Subtraction - Whole Number - Within 5
- Picture Numbers - Subtracting - Picture and Instruction to Number (Within 5)
Units Teaching This Skill
These adaptive units introduce, teach, or reinforce this skill (Subtract within 20) through scaffolded problems that grow in difficulty as concepts are understood.