Mathematics › lesson 02 of 100 · Beginner

Addition and Subtraction

You can add and subtract numbers within 100 to solve problems.

Imagine you have 15 pencils in your pencil case and your friend gives you 7 more. To find out how many pencils you have now, you need to add 15 and 7. This is a basic math operation that helps you calculate the total amount of things you have.

When you add numbers, you are counting how many things you have in total. For example, if you have 5 toys and you get 2 more, you now have 7 toys.

On the other hand, when you subtract numbers, you are finding the difference between two amounts. For instance, if you have 12 crayons and you give 4 to your brother, you will have 8 crayons left.

예시

• 35 + 17 =Add 35 and 17 to find the total.
• 45 - 23 =Subtract 23 from 45 to find the difference.
• 75 + 25 =Add 75 and 25 to find the total.

전체 과정은 수업마다 5문제로 확인하고, 내 단계에 맞추며, 멈춘 자리를 기억합니다.