Addition & Subtraction
Putting groups together, and taking groups apart.
What is addition?
Addition means putting groups together to find out how many there are in all. If you have 3 crayons and a friend gives you 4 more, you now have 3 + 4 = 7 crayons. The plus sign (+) is how we write "put together."
What is subtraction?
Subtraction means taking some away from a group to see how many are left. If you have 8 cookies and eat 5, you have 8 − 5 = 3 cookies left. The minus sign (−) is how we write "take away."
Fact families
Addition and subtraction are best friends — they undo each other. If 3 + 4 = 7, then 7 − 4 = 3 and 7 − 3 = 4. Numbers like 3, 4, and 7 that fit together like this are called a fact family, and knowing one fact helps you know the others.
Quick quiz: Addition & Subtraction
Question 1 of 5