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Grade 1 (age 6-7)

Subtraction Basics

Subtraction Basics

Subtraction is how we take some away from a whole and find how many are left. If you have 7 cookies and eat 2, then 5 remain; we write it with the minus sign: 7 − 2 = 5. Here you slide the cookies and how many are eaten, then move left along the number line to count what stays. Addition and subtraction are partners: knowing 3 + 4 = 7 tells you 7 − 4 = 3.

What is Taking Away?
✂️ Taking Away = Subtracting
①You have 5 cookies, ate 2
②How many left? → 3!
③This is "subtraction"
④The symbol for taking away is −
Let's Eat Cookies
7
3
💡 Understanding Subtraction
①Take some away from the total → the rest remains
②The X marks are the eaten cookies
③7 − 3 = 4 → "7 minus 3 is 4"
④Try changing the slider!
Subtracting on a Number Line
8
3
⬅️ Subtracting on a Number Line
①The red dot is the starting number
②The dashed arc moves left by the amount subtracted
③The green dot is the answer!
④Subtracting moves left on the number line
Addition and Subtraction are Friends!
🤝 Addition ↔ Subtraction
①If 3 + 4 = 7
②Then 7 − 4 = 3
③And 7 − 3 = 4 too!
④Knowing addition helps with subtraction
Summary
Subtraction Symbol
Total − Subtract = Remaining
Minus (−) means taking some away
Subtracting 0
Any number − 0 = same number
Subtracting 0 keeps the same value (nothing taken)
Subtracting Same Number
Any number − itself = 0
Take all → nothing left
🎯 Remember!
①Subtraction is "taking away"
②The − sign means "minus"
③Move left on a number line
④Subtract 0 → same; subtract all → 0
⑤Addition and subtraction are partners!
Examples and Unit Test
Example 1
There are 7 cookies. If you eat 2 of them, how many cookies are left?
1
Take away the 2 eaten from the total of 7.
2
7 − 2 = 5, so 5 cookies are left.
▸ 5 cookies
Subtracting means taking part away from the whole.
Example 2
Given 3 + 4 = 7, use it to find 7 − 4.
1
Think of the addition fact 3 + 4 = 7 in reverse.
2
Taking 4 from 7 leaves 3, so 7 − 4 = 3.
▸ 3
Knowing an addition fact instantly gives you the matching subtraction answer.
Unit Test
What is the value of 6 − 4?
①1
②2
③3
④10
▸ ② 2
1
Take 4 away from 6.
2
6 − 4 = 2.
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Addition Basics
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Carrying and Borrowing