The document provides information about adding and subtracting decimals. It begins by stating the objectives of understanding how to add and subtract decimals through thousandths and solve word problems involving decimals. It then provides examples of how to add and subtract decimals by lining up the decimal points and adding zeros as placeholders when needed. It demonstrates estimating sums and differences by rounding decimals. Finally, it includes practice problems involving adding, subtracting, and estimating decimals, as well as word problems requiring the application of decimal operations.

2. Quote of
the
Day
November 9, 2021
Tuesday

5. Let’s Recall

6. Adding and
Subtracting
Decimals

7. Get a strong understanding of the very basic of
Addition and Subtraction of Decimals. Adding and
subtracting decimals happens a lot in the real world.
You may find that you need to add up the cost of your
daily groceries to see if you have enough money to pay
for them. Or perhaps you need to subtract the cost of
the Ice cream from your own wallet. In this lesson, you
will learn how to add and subtract decimals.

8.  Add and subtract decimals through thousandths
 Estimate the sum and difference of decimal numbers
 Solve word problems involving addition and subtraction of
decimals
OBJECTIVES

10. Do you know the steps in adding and subtracting numbers?
Are you familiar with the three important steps to remember
in Adding and Subtracting decimals?

12. Let’s

13. Adding Decimals Through Thousandths

14. Step 1: Line up the numbers vertically so that the decimal
points all lie on a vertical line.
Step 2: Add extra zeros to the right of the number so that
each number has the same number of digits to
the right of the decimal place.
Step 3: Add the numbers. Place the decimal point of the
result in line with the other decimal

15. Example: Add 1.452 to 1.3
1.452
+ 1.3
Line up the decimal points
00
Add Zeroes
Add
2
5
7
.
2

16. Example: 3.25, 0.075 and 5
3.25
0.075
+ 5.
0
000
5
2
3
.
8

17. Subtracting Decimals Through Thousandths

18. Step 1: Line up the numbers vertically so that the
decimal points all lie on a vertical line.
Step 2: Add extra zeros to the right of the number so that
each number has the same number of digits to
the right of the decimal place.
Step 3: Subtract the numbers. Place the decimal point of
the result in line with the other decimal

19. Example: What is 7.368 - 1.15
7.368
− 1.15
Line up the decimal points
0 Add Zero
Subtract
8
1
2
.
6

20. Check: 7.368 minus 1.15 equals 6.21
6.218
+ 1.15 0
8
6
3
.
7

21. 1. Junrey is filling his fish tank up with water. The tank holds 20 gallons
altogether. Junrey starts with 4 gallons already in the tank. Then, he
uses a 2 gallon container to add the water. How many containers of 2
gallons does he need to fill up the tank?
Take note about putting in zeros:
Why do we put in extra zeros?
A zero is really saying "there is no value at this decimal place".
• In a number like 10, the zero is saying "no ones"
• In a number like 2.50 the zero is saying "no hundredths"
So it is safe to take a number like 2.5 and make it 2.50 or 2.500 etc.
But DON'T take 2.5 and make it 20.5, that is plain wrong

22. 2. Uncle Ben has 440 chickens on his farm. 39 are roosters and the
rest are hens. 15 of his hens do not lay eggs. The rest lay eggs. How
many egg-laying hens does Uncle Ben have on his farm?
Estimating Sums and Differences

23. 3. Peter has four horses. Each one eats 4 pounds of oats twice a day.
How many pounds of oats does he need to feed his horses for 3
days?
To estimate means to find an answer that is close to but not exact. It is a
reasonable answer to a problem.
The easiest way to estimate a sum or a difference of decimals is to round
the decimal. If you round the decimal to the nearest whole number, you
can complete the problem using mental math or at least simplify the
problem so that finding an answer is easier.

24. Example: 1. We will round each number to the
nearest hundredth number. much did
Estimate the sum of 5.97 + 8.19.
5.97 + 8.19 = ?
6 + 8.20 = ?

25. 5. Zach had 700 marbles. ?He shared 145 marbles and put the
remaining marbles equally in 5 many marbles were in each jar?
6 + 8.20 =?
6.
+ 8.20
00
0
2
.
14
The sum is about 14.20
5.97
+ 8.19
6
1
.
14

26. Estimate the difference of 87.33 - 12.1
87.33 - 12.10 =?
87 - 12 =?
87
- 12
5
7

27. 5. Zach had 700 marbles. He shared 145 marbles and put the
remaining marbles equally in 5 jars. How many marbles were in each
jar?
Solving Word Problems

28. 5. Zach had 700 marbles. He shared 145 marbles and put the remaining
Via was 88.49 cm tall when she was 3 years old. By the time she was 18, Via had
grown further by 83.91 cm. How tall was she when she was 18? marbles equally
in 5 jars. How many marbles were in each jar?
Example 1
Solution:
88.49
+ 83.91
0
4
.
2
17
Thus, Via was 172.40 cm when she was 18 year

29. jaExample 2
Lauren decided that it was time for a new haircut. With hair
74.2 cm long, she went to the hair dresser. When she left, it was 21.6
cm long. How long did the hairdresser cut from Laurens originally
longer hair?
74.2
21.6
-
6
6
.
2
5
Therefore, the hairdresser cut off 52.6 cm
from Lauren’s hair.

31. A.Add the following set of
decimals.
1. 38.12 + 12.24
2. 83.25 – 14.25
3. 45.19 – 15.92
4. 35.15 + 15.15
5. 54.32 + 20.3
B. Estimate the sums and
differences.
1. 96.85 + 45.25
2. 85.42 – 65.12
3. 65.12 – 12.53
4. 8.4 + 4.1
5. 18.2 – 4.8

32. 5. Zach had 700 marbles. He shared 145 marbles and put the
remaining marbles equally in 5 jars. How many marbles were in each
jar?
C. Solve the following problems.
1. Sam had P50.75. He gave P18.50 to Maria to buy a book. How much money
does he have left with him?
2. Gina purchased a school bag for P105.55, books for P95.35, and a pen for
P25.25 What is the total amount that she spent?

33. 3. John withdrew P175.75 from his bank account. Now he has
P450.25 left in his account. What was the original balance in his
account before the withdrawal?
4. Matthew walked 1.35 kilometers in the first day, 1.49 kilometers in
the second day, and 1.75 kilometers in the third day. How much total
distance did he walk in the three days?
5. Peter went to a store. He bought 5.20 lbs. of jelly beans and
cherries. If 3.24 lbs. were jelly beans, how many pounds were
cherries?

34. A. Add the following set of decimals.
1. 38.12 + 12.2 2. 83.25 – 14.2
Solution: Solution:
38.12
+ 12.2
2
3
.
0
5
83.25
– 14.2 0
5
4
.
7
9
0

35. 3. 45.19 – 15.92 4. 35.15 + 15.15
Solution: Solution:
45.19
– 15.92
7
2
.
9
2
35.15
+ 15.15
0
3
.
0
5

36. 5. 54.32 + 20.3
Solution:
54.32
+ 20.3 0
2
6
.
4
7

37. B. Estimate the sums and differences.
1. 96.85 + 45.25
Solution:
96.85 + 45.25 =?
96.90 + 45.30
96.90
+ 45.30
0
2
.
2
14

38. 2. 85.42 – 65.12
Solution:
85.42 - 65.12 =?
85.40 - 65.10
85.40
65.10
-
0
3
.
0
2

39. 3. 65.12 – 12.53
Solution:
65.12 - 12.53 =?
65.10 - 12.50
65.10
-
12.50
0
6
.
2
5

40. 4. 8.4 + 4.1
Solution:
8.4 + 4.1 =?
8 + 4 = 12

41. 5. 18.2 – 4.8
Solution:
18.2 - 4.8 =?
18 - 5 = 13

42. 1. Sam had P50.75. He gave P18.50 to Maria to buy a book. How much
money does he have left with him?
Solution:
P50.75
-
P18.50
5
2
.
2
3
P Total money left
with Sam

43. 2. Gina purchased a school bag for P105.55, books for P95.35, and a
pen for P25.25 What is the total amount that she spent?
Solution: P105.55
P 95.35
P 25.25
+
5
1
.
6
2
2
P
The total amount
Gina spent

44. 3. John withdrew P175.75 from his bank account. Now he has
P450.25 left in his account. What was the original balance in his
account before the withdrawal?
Solution:
P 175.75
P 450.25
+
0
0
.
6
2
6
P
The original balance
in John’s account

45. 4. Matthew walked 1.35 kilometers in the first day, 1.49
kilometers in the second day, and 1.75 kilometers in the third day.
How much total distance did he walk in the three days
Solution: 1.35
1.49
1.75
+
9
5
.
4 km
The total distance
Matthew walk
in three days

46. 5. Peter went to a store. He bought 5.20 lbs. of jelly beans and
cherries. If 3.24 lbs. were jelly beans, how many pounds were
cherries?
Solution:
5.20
-
3.24
6
9
.
1 lbs. Cherries