Adding and Subtracting Multiples of 10

Lesson 7

Today we will…

Add and subtract tens-
numbers such as 20, 30, 40,
and 50.

Add/ Sumar

Addition/ Adición,

Suma

Subtract/ Restar

Subtraction

Equation/ Ecuación

de resta

Minus/ Menos

Jump/Salto

1

2

3

4

5

6

50 + 20 = _____

Adding 20 is like adding 10
and then adding 10 again.

Modeling
Adding 20

DID YOU KNOW?

That starting number is 50.

- I will make two jumps down of 10 each.

- Each jumps add 10.

- I end up at 70.

Adding with
an open
number line.

Watch as I show the same problem with an open number
line. I start at 50. I know that adding 20 is the same as
adding 10 two times, so I’ll make two jumps of 10
moving forward. I end up at 70.

50 + 20 = 70

+10

+10

Second Way to
Represent the

Addition

I can draw a
different open
number line for
this problem. I
know that two
10s is 20, so I
can just make
one jump of 20.

Second Way to Represent the Addition

50 70

+20

Subtracting on the Pocket Wall

Chart

60 – 40 = ______

-Where do I start? ______

-How many 10s is 40? _____

-What jumps do we make? ______

-Where do we end up? _______

Now, I will show the same problem with an
open number line.
-Where do I start? ______

-What jumps do I make?
________________

-Where do I end up? _______

20 30 40 50 60

-10

-10

-10

-10

Let’s go to

I will write problem

one!

We’ll solve this problem together. As I draw the open number lines on the board, you record them on

page 15.

37 - 20 = ____

Where do we start?

What jumps can we

make?

Where do we end up?

What equation can we
write for this problem?

Let’s go to

Work with a partner!

WorkSpace Page
16

●

You will work on this page on your own.

You all!!

You have successfully completed

This course.

Congratulations!

Date

Signature

03/14/2023