Page 81 - SK Year 5 Mathematics DLP

ADDITION AND SUBTRACTION OF DECIMALS

1 22.302 km
28.9 km Q S R

17.45 km
P

Based on the diagram above, calculate the distance from P to S.
28.9 km + 22.302 km – 17.45 km = km

Step 1 Solve addition before
Step 2
doing subtraction.
1 1
2 8 . 9 0 0 10 11
+ 2 2 . 3 0 2 4 0 1 10
5 1 . 2 0 2 5 1 . 2 0 2
– 1 7 . 4 5 0
3 3 . 7 5 2
Align the decimal points.

28.9 km + 22.302 km – 17.45 km = 33.752 km

The distance from P to S is 33.752 km.

2 74.285 + 9.607 – 18.043 =

Method 1 Method 2

1 1 6 14
7 4 . 2 8 5 7 4 . 2 8 5
+ 9 . 6 0 7 – 1 8 . 0 4 3 Are both calculations
8 3 . 8 9 2 5 6 . 2 4 2 correct? Discuss.

7 13 8 12 1
8 3 . 8 9 2 5 6 . 2 4 2
– 1 8 . 0 4 3 + 9 . 6 0 7
6 5 . 8 4 9 6 5 . 8 4 9

74.285 + 9.607 – 18.043 = 65.849

• Relate mixed operations involving addition and subtraction of decimals to daily
life situations such as sports event scores, daily allowances, and expenses. 73
2.2.2 • Carry out group activities and ask pupils to present their calculations.