Subtraction — 1st Grade Lesson
Students will subtract within 20, connect subtraction to addition, and solve take-away and comparison problems.
1st Grade · Subtraction · ~20 min lesson
What is subtraction?
Subtraction is taking away from a group, or finding the difference between two numbers. The number you start with is the minuend, the number you take away is the subtrahend, and the answer is the difference.
8 - 3 = 5 minuend - subtrahend = difference
Strategy 1: Take away (cross out)
Draw the starting number of objects, then cross out what you take away. What’s left is the answer.
7 - 3: draw 7 dots, cross out 3, count the rest: 1, 2, 3, 4 → 4.
Strategy 2: Count back
Start at the bigger number and count backward.
7 - 3: start at 7, count back 3: 6, 5, 4 → 4.
Strategy 3: Use addition (fact families)
Subtraction and addition are opposites. Learn them together as a fact family:
7 + 5 = 12, so 12 - 7 = 5 and 12 - 5 = 7.
Subtraction with zero
- Any number minus 0 is itself: 9 - 0 = 9.
- A number minus itself is 0: 9 - 9 = 0.
How to practice at home
- Snack math: “You have 6 crackers. Eat 2. How many left?”
- Count back on fingers: start at the number and fold fingers down.
- Fact families: give one fact (7 + 5 = 12) and ask for the other three.
- Cross-out drawing: draw and cross out objects on paper.
Practice with the exercises above, then download these free printable worksheets:
Practice Exercises
Try these on your own, then reveal the answer to check.
What is 7 - 3?
💡 Count back from 7: 6, 5, 4.
What is 10 - 4?
💡 4 and 6 make a ten.
What is 9 - 0?
💡 Taking away nothing leaves everything.
What is 15 - 5?
💡 Take away the ones — 5 from 15 is 10.
Fill in the missing number: 12 - ___ = 7
💡 7 + 5 = 12, so 12 - 5 = 7.
There are 8 apples. You eat 3. How many are left?
💡 8 - 3 = 5.
Printable Worksheets
Put this lesson into practice with free, printable worksheets — each with an answer key.
Before You Start
- Addition facts to 10
- Counting to 20
Common Mistakes to Watch For
- Subtracting the wrong order (always bigger minus smaller)
- Forgetting that 5 - 0 = 5, not 0
What to Learn Next
Browse more Subtraction worksheets or explore all 1st Grade worksheets.
Related Worksheets
Subtraction Within 10 Worksheet
Practice subtraction facts within 10, using a number line to count back to the answer.
Subtraction Within 20 Worksheet
Practice subtraction within 20, using a number line to count back or count up to the answer.
Subtraction Word Problems Worksheet
Subtraction shows up in stories as things being taken away or compared. Solve each story problem and label your answer.
Frequently Asked Questions
How do I help my child subtract within 20?
Teach subtraction as the opposite of addition: if they know 7 + 5 = 12, then 12 - 7 = 5 and 12 - 5 = 7. Counting back and drawing circles to cross out also work.
What does subtract within 20 mean?
Solving problems where both numbers are between 0 and 20, such as 15 - 8 = 7. Students use objects, fingers, or counting-back strategies.
Original & reviewed. Every worksheet is created in-house from a grade-level skill brief, checked for a correct answer key, and reviewed for grade-appropriateness. Our editorial policy.