DECIMALS

1
DECIMALS
65.1
50.34
1,234,567
18.0076
2
Adding, subtracting, Multiplying Dividing
Decimals.
Example Subtract 3.0025 from 12.1
12.1000
Solution
N.B. For adding and subtracting decimals keep
the decimal points lined up
-
3.0025
9.0975
3
Example Multiply 576 by 23
576
Solution
x
23
1728
11520
13248
4
Example Multiply 12.36 from 4
12.36
Solution
( 2 d.p.)
x
4
( 0 d.p.)
49.44
( 2 d.p.)
NB When multiplying decimal numbers. Ignore the
decimal point until the very end i.e. 12.36 has 2
d.p. 4 has 0 d.p. Therefore Answer will have (2
0) 2 dec places
5
Example Multiply 2.31 by 0.7
2.31
Solution
( 2 d.p.)
Total 3 d.p.
x
0.7
( 1 d.p.)
1.617
( 3 d.p.)

6
Example Multiply 25.6 by 4.7
25.6
Solution
( 1 d.p.)
2 d.p.
x
4.7
( 1 d.p.)
1792
1024

120.32
( 2 d.p.)
7
Example (dividing by a whole no.) Divide 27.052
by 8
Solution

3.
3
8
1
5
8
27.0520
8
Example (dividing by a decimal) Divide 34.86 by
0.7
Solution Write 34.86 0.7 as a fraction
NB The method here is to make the 0.7 into a
whole number remembering that what we do to the
bottom no. we must do to the top so they are
equivalent.
9
Divide 34.86 by 0.7
Solution contd.
4
9.
8

8
348.6
ANS 49.8
10
Example (dividing by a decimal) Divide 3.6 by
0.04
Solution

90
ANS 90
4
360
11
Working with powers of 10 Examples Eg (exempli
gratia)
2.56 x 10 25.6
2.56 x 1000 2560
31.8 10 3.18

5.56 1000 0.00556
12
Further Examples Eg (exempli gratia)
2.89 x 20 28.9 57.8
0.4261 x 300 42.61 x 3 127.83
45 40 4.5 4 1.125

31.92 3000 0.03192 3
0.01064