Adding and Subtracting

1
Adding and Subtracting Decimals
2
Rules of adding and subtracting decimals
4.5 -3.85

1. Line up the decimals
2. Place zeros in the problem to help keep the place
   value aligned
3. Solve the problem
4. Carry the decimal straight down

4.5 3.85
-
4.50 3.85
-
4.50 3.85
-
065
0.65
3
Some examples
35.1
4
.789
0.789
1.490
1.49

2.279
5
4.847
1.22
1.220
-
3.627
6
Adding Subtracting DecimalsCompetition

• How to Play
• The object of the game Solve the problem
  accurately
• You will be split into teams
• Each team will be numbered
• Everyone will solve the same problem, but one
  team will be selected at random to share their
  answer.
• If their answer is correct, they earn a point
• If their answer is incorrect, another team can
  steal the point by answering it correctly
• Whoever has the most points at the end of the
  game wins
• Your team can lose points by being off task or by
  having poor sportsmanship

7
Ready
Set
Go!
8
2.093
9
Ready
Set
Go!
10
0.4
11
Ready
Set
Go!
12
5.004
13
Ready
Set
Go!
14
1.67
15
Ready
Set
Go!
16
4.35
17
Ready
Set
Go!
18
21.16
19
Ready
Set
Go!
20
6.4058
21
Ready
Set
Go!
22
3.43
23
Ready
Set
Go!
24
2.96
25
Ready
Set
Go!
26
9.413
27
Ready
Set
Go!
28
1.387
29
Ready
Set
Go!
30
0.393
31
Ready
Set
Go!
32
1.111
33
Ready
Set
Go!
34
12.2
35
Ready
Set
Go!
36
1.265
37
Ready
Set
Go!
38
0.225
39
Ready
Set
Go!
40
22.1
41
Ready
Set
Go!
42
5.998
43
Ready
Set
Go!
44
0.388
45
Ready
Set
Go!
46
5.33
47
Ready
Set
Go!
48
50
49
Ready
Set
Go!
50
35.99
51
Ready
Set
Go!
52
4.476
53
Ready
Set
Go!
54
28.895
55
Ready
Set
Go!
56
5.772
57
Bonus Question!
As a group, list the 4 rules for adding
or subtracting decimals.
58
Answer

1. Line up the decimals
2. Place zeros into the problem to hold place value
3. Carry the decimal straight down