Lesson 8.5 Number pairs to 100

Lesson 8.5 Number pairs to 100

What is 100-90?

• 10-9=1

• 100-90=10

We can also use a number pair to show this;

Try this! Find the missing number.

When we add numbers mentally , we are trying to find a quick way of adding the numbers in our heads.

• What is 20+8+80?

To add three numbers mentally by first finding a pair of number that make 100, then adding the remaining number to it.

Multiple Select

Wait...

What have you learned so far?

• number pairs

• finding a pair of number that make 100

what is 70 + 40 + 50?

how do you solve this?

70 and 30 make 100

30 come from 40

since we took 30 so there are 10 left.

70 and 30 make 100. write number sentence.

• 70+30=100

• 100-70=30

• It is wrong when you write as

• 50+50=100

• or

• 80+20=100

• because you did not follow your number pair which is 70 and 30 make 100.

Drop your comment in Google classroom private message if you need help.

Let's, do your Google slides and Quizziz practice.