Subtraction - First Grade Complete Guide
1. Subtraction Facts - Numbers up to 10
Concept: Learn basic subtraction by taking away numbers from 0 to 10.
Formula: a - b = c (where a, b, c are numbers from 0 to 10)
Examples:
10 - 3 = 7
8 - 5 = 3
6 - 2 = 4
9 - 9 = 0
💡 Tip: Count backwards or use fingers to find the answer!
2. Ways to Make a Number - Subtraction Sentences
Concept: Find different subtraction sentences that give the same answer.
Formula: Different numbers - different numbers = same result
Ways to make 3:
5 - 2 = 3
6 - 3 = 3
8 - 5 = 3
10 - 7 = 3
💡 Tip: Many different subtractions can give the same answer!
3. Ways to Subtract from a Number
Concept: Find all the ways to subtract different numbers from one starting number.
Formula: Same starting number - different numbers = different results
Ways to subtract from 8:
8 - 1 = 7
8 - 2 = 6
8 - 3 = 5
8 - 4 = 4
💡 Tip: Start with the same number and subtract smaller numbers!
4. Make a Number Using Subtraction - Numbers up to 10
Concept: Create a target number by choosing the right subtraction sentence.
Formula: ? - ? = target number
Make 5:
10 - 5 = 5 ✓
9 - 4 = 5 ✓
7 - 2 = 5 ✓
6 - 1 = 5 ✓
💡 Tip: Think of what number minus what equals your target!
5. Complete the Subtraction Sentence
Concept: Fill in the missing number in a subtraction sentence.
Formula: a - ? = c OR ? - b = c OR a - b = ?
Examples:
9 - ? = 4 → 9 - 5 = 4
? - 3 = 5 → 8 - 3 = 5
7 - 2 = ? → 7 - 2 = 5
💡 Tip: Use addition to help find missing numbers!
6. Subtraction Word Problems - Numbers up to 10
Concept: Solve real-life problems using subtraction with numbers up to 10.
Formula: Total - Taken Away = What's Left
Example:
"Sara has 8 apples. She gives 3 to her friend. How many apples does Sara have left?"
8 - 3 = 5 apples
💡 Tip: Look for keywords like "left", "gave away", "lost", "ate"!
7. Subtraction Sentences for Word Problems - Numbers up to 10
Concept: Write the correct subtraction sentence from a word problem.
Formula: Read → Identify Numbers → Write Subtraction
Problem:
"Tom had 9 balloons. 4 flew away."
Sentence: 9 - 4 = 5
💡 Tip: Start number comes first, subtract what's taken away!
8. Subtraction Facts - Numbers up to 18
Concept: Learn subtraction with larger numbers from 11 to 18.
Formula: a - b = c (where a can be up to 18)
Examples:
18 - 9 = 9
15 - 7 = 8
13 - 5 = 8
11 - 3 = 8
💡 Tip: Break larger numbers into 10 + extra to make subtraction easier!
9. Subtraction Using Number Lines - Numbers up to 18
Concept: Use a number line to visualize subtraction by moving backwards.
Formula: Start at first number → Jump backward by second number → Find answer
Example: 14 - 5 = ?
Start at 14 → Jump back 5 spaces → Land on 9
Answer: 14 - 5 = 9
💡 Tip: Draw a number line and hop backwards!
10. Subtraction Word Problems - Numbers up to 18
Concept: Solve word problems with numbers from 11 to 18.
Formula: Starting Amount - Amount Removed = Result
Example:
"There are 16 birds on a tree. 8 fly away. How many birds are left?"
16 - 8 = 8 birds
💡 Tip: Circle the numbers and the action word!
11. Subtraction Sentences for Word Problems - Numbers up to 18
Concept: Write the matching subtraction sentence for a word problem (11-18).
Formula: Story → Numbers → Subtraction Sentence
Problem:
"Maya has 17 stickers. She uses 9 stickers."
Sentence: 17 - 9 = 8
💡 Tip: Identify what you start with and what gets taken away!
12. Make a Number Using Subtraction - Numbers up to 20
Concept: Find different ways to create a target number using subtraction up to 20.
Formula: Various subtractions = Target Number
Make 7:
15 - 8 = 7
12 - 5 = 7
18 - 11 = 7
20 - 13 = 7
💡 Tip: Many different problems can have the same answer!
13. Related Subtraction Facts
Concept: Understand the relationship between subtraction facts in the same family.
Formula: If a - b = c, then a - c = b
Fact Family Example:
10 - 6 = 4
10 - 4 = 6
(Both use numbers 10, 6, and 4)
💡 Tip: Fact families use the same three numbers!
14. Subtraction Sentences: True or False?
Concept: Determine if a subtraction sentence is correct or incorrect.
Formula: Check if a - b = c is correct
Examples:
9 - 4 = 5 → TRUE ✓
7 - 2 = 4 → FALSE ✗
12 - 5 = 7 → TRUE ✓
8 - 3 = 6 → FALSE ✗
💡 Tip: Solve it yourself first, then compare answers!
15. Subtract One-Digit from Two-Digit - Without Regrouping
Concept: Subtract a small number from a bigger number when you have enough ones.
Formula: Tens stay the same, subtract from ones place
Examples:
38 - 5 = 33 (8 ones - 5 ones = 3 ones)
47 - 3 = 44 (7 ones - 3 ones = 4 ones)
29 - 4 = 25 (9 ones - 4 ones = 5 ones)
💡 Tip: Only subtract from the ones place when there are enough ones!
16. Subtract One-Digit from Two-Digit - With Regrouping
Concept: Borrow from tens when there aren't enough ones to subtract.
Formula: Borrow 1 ten = 10 ones → Add to ones place → Subtract
Examples:
32 - 5 = 27 (Borrow: 2 tens 12 ones - 5 = 2 tens 7 ones)
41 - 6 = 35 (Borrow: 3 tens 11 ones - 6 = 3 tens 5 ones)
53 - 8 = 45 (Borrow: 4 tens 13 ones - 8 = 4 tens 5 ones)
💡 Tip: When ones are too small, borrow 10 from the tens place!
Important Subtraction Terms
Minuend: The starting number
Subtrahend: Number being subtracted
Difference: The answer
Regrouping: Borrowing from tens
Quick Subtraction Tips
- ✓ Subtraction means "taking away"
- ✓ The bigger number always comes first
- ✓ You can check subtraction with addition
- ✓ When you subtract 0, the number stays the same
- ✓ Any number minus itself equals 0
- ✓ Use number lines, fingers, or objects to help
- ✓ Look for keywords in word problems: left, gave away, lost, flew away, ate
🌟 Remember 🌟
Practice makes perfect! The more you practice subtraction, the faster and better you'll become at solving problems!