1. Module 2
Lesson 8
Solve Addition and Subtraction Word Problems Using the Ruler as a Number Line

2. Review
For Valentine’s Day, Suzie is mailing a painting to her Nana. The painting is 16cm. Long. The gift box is 35 cm. long. How much longer is the gift box than the painting? Draw a picture to show your work.

3. I am throwing a party and want to decorate my house
I am throwing a party and want to decorate my house. I will start with my front door and put some ribbons around the edges. How can we figure out how long the ribbon should be?
What measurement tools can I use?

4. Draw the door and its measurement
These are the measurements for the door. Does that help us?
1 m.
Draw the door and its measurement ?
2 m. ?

5. Write a number sentence to show
How long does the ribbon need to be to go all the way around the door?
1 m.
Write a number sentence to show
your work ?
2 m.
______+______+______+______=______ ?

6. I also want to string lights up on one side of the steps
I also want to string lights up on one side of the steps. Help me figure out the length of the sting lights for two steps.
12cm.
8cm.

7. 12cm. 8cm. How many centimeters of lights do I need for two steps?
Use a centimeter ruler to help you find the length

8. Let’s use a ruler to help us measure and add
1. Start at the 0 and slide to 8.
2. Slide your finger to 2 more now where are we?
3. How many more do we need to slide?
4. Now where did your finger stop?

9. Let’s use a ruler to help measure and add the second step
1. Start at the 0 and slide to 8.
2. Slide your finger to 2 more now where are we? Great! You made a ten.
3. How many more do we need to slide?
4. Now where did your finger stop?

11. 12cm. 12cm. 8cm. 8cm. So, 20cm. + 20 cm. += _____ cm.
How many centimeters of lights do I need for two steps?
12cm.
12cm.
8cm.
8cm.
So, 20cm cm. += _____ cm.

12. I have a string of lights that is 1 meter long
I have a string of lights that is 1 meter long. Is that long enough to reach the two steps?
12cm.
12cm.
8cm.
8cm.
20cm cm. += 40 cm.

13. Yes, because …
1cm. = 1cm.
10 cm. = 1 decimeter
100 cm. = 1 meter

14. Party Sign
We want to hang a party sign with a piece of string. Oh no! Our centimeter ruler broke and starts at 4 cm.

15. Now, what if I wanted to start at the top of the step, at 8 cm
Now, what if I wanted to start at the top of the step, at 8 cm. How can I determine how long the string of lights should be?
8cm.
12cm.
Use a centimeter ruler to help you find the length

16. Let’s use a ruler to help measure and add the second step
Start at the 8cm. pretend it’s zero
Move your finger 2 spaces. Where are you? 10cm.
Now, let’s count the rest of the steps in groups of ten.
Remember how we moved 2 fingers spaces to get to ten?
Now we have to subtract 2 finger spaces from our total.