1. Add and subtract decimals (5.N.B.T.7)
NYS Math Module 1
Lesson 10
Objective: Subtract decimals using place value strategies and relate those strategies to a written method.
I can...
Add and subtract decimals (5.N.B.T.7)
Take out the unit (5.N.B.T.1)

2. Take out the Unit Say this number: 76.358 = 7 tens _____ thousandths
6358
= 763 tenths _____ thousandths 58
= _____ hundredths 8 thousandths
7635

3. Adding Decimals Write the following addition sentence in decimal form.
3 tenths + 2 tenths = _______
Now solve it: = _____
0.5
Two more. Rewrite them in decimal form and solve
5 hundredths + 4 hundredths = _______
= 0.09
35 hundredths + 4 hundredths = _______
= 0.39

4. One Unit Less Say the decimal that is one less than the unit given.
5 tenths
3 tenths
1 tenth
Let’s try it with hundredths.
5 hundredths
3 hundredths
1 hundredth
Let’s try it with thousandths.
5 thousandths
3 thousandths
1 thousandth

5. 0.029 0.028 0.51 0.06 Write the decimal that is one less thousandth.
What is one tenth less than 0.61?
0.51
0.06
What is 1 thousandth less than 0.061?

6. One more..
0.539
What is one hundredth less than 0.549?

7. .Word Problem
At the 2012 London Olympics, Michael Phelps won the gold medal in the men’s 100 meter butterfly. He swam the first 50 meters in seconds. The second 50 meters took him seconds. What was his total time?
52.35

8. Since they are both tenths, you can simply subtract 5 – 3.
.Concept Development
Read this problem aloud:
5 tenths – 3 tenths = _______
2 tenths
Tell your partner how you are going to solve this problem.:
Since they are both tenths, you can simply subtract 5 – 3.

9. Only LIKE units are being subtracted
Some tips to remember.
Write the decimals in standard form.
Line up the decimals.
Add zeros in all the empty spaces.
Find the difference:
7 ones 5 thousandths – 2 ones 3 thousandths
Only LIKE units are being subtracted
7.005
2.003 -
5.002

10. - 900.05 000.03 900.02 Read carefully and rewrite the decimals.
9 hundreds 5 hundredths – 3 hundredths
Tell your neighbor how to solve this one.
Now, solve it vertically.
900.05
000.03 -
900.02

11. 83 tenths – 6.4 = _____
How is this problem different from the problems we’ve done previously?
Write it vertically or use your place value chart, so you can see the difference.
8.3
6.4 - 7 1
We need to regroup.
1.9

12. Try another one on your own.
9.2 – 6 ones 4 tenths = _____
Discuss how you solved this problem with a partner.
9.2
6.4 - 8 1
Did you regroup?
2.8

13. 0.831 – = _____
How did you solve this problem?
First, write the problem vertically.
Make sure you regroup. 7 12
0.831
0.292 - 1
0.539

14. 4.003 – 1.29 = _____
Rewrite the problem vertically.
What do you notice about the thousandths place?
Turn and tell your partner.
That’s right. We need to add a zero So instead of 29 hundredths, we think of it as 290 thousandths. Solve it. 39 1
4.003
1.290 -
2.713

15. - 59 6.00 0.48 1 6 – 0.48 = _____ 5.52 Say this problem aloud.
How can we think of 6 wholes in the same units as 48 hundredths?
Is there another way to write 6 wholes? 59 1
6.00
0.48 -
5.52

16. Let’s try one more:
13.2 – 5.08 1 1
13.20
05.08 -
08.12

17. Problem Set Review 5 1 5.1 4 3 40.3 Example #1:
5 ones 3 tenths – 2 tenths = ______ones______tenths=_____ 5 1
5.1
3 tenths – 2 tenths = 1 tenth
There is only 5 ones, so 5 – 0 = 5
Rewrite 5 ones and 1 tenth
You try:
4 tens 8 tenths – 5 tenths = ______tens______tenths=_____ 4 3
40.3

18. - - 2.6 – 0.4 = 2.6 0.4 2.2 6 – 15 tenths = 6.00 1.50 4.50 Example #2:
1.) Rewrite the problem
2.) Solve it
2.2
Example #3:
6 – 15 tenths = -
6.00
1.50
1.) Rewrite the problem
4.50
2.) Add “zeros” if needed
3.) Solve it

19. Thank you for your purchase.
Fonts, backgrounds, and clip art provided by:
Melody
Graphics by: TeachesThirdinGeorgia

21. Exit Ticket Exit Ticket Exit Ticket Exit Ticket
Subtract
1.7 – 0.8 = ______ tenths - ______ tenths = _______ tenths=_______
Subtract vertically, showing all work.
a – = _________
b. 7 – 0.35 = __________
Subtract
1.7 – 0.8 = ______ tenths - ______ tenths = _______ tenths=_______
Subtract vertically, showing all work.
a – = _________
b. 7 – 0.35 = __________
Exit Ticket
Exit Ticket
Subtract
1.7 – 0.8 = ______ tenths - ______ tenths = _______ tenths=_______
Subtract vertically, showing all work.
a – = _________
b. 7 – 0.35 = __________
Subtract
1.7 – 0.8 = ______ tenths - ______ tenths = _______ tenths=_______
Subtract vertically, showing all work.
a – = _________
b. 7 – 0.35 = __________