Transcript Decimals - Qatar University
Decimals
Addition & Subtraction
Example Find: 15.12 + 3.2 - 12.04
Solution: 15.12 + 3.2 = 15.12 + 3.20 = 18.32
15.12 + 3.2 - 12.04
=18.32 – 12.04 = 6.28
Multiplication
Example
Find: 12.5
x
35.02
Solution (1) First multiply: 125 x 125 x 3502 = 437750 3502 (2) Second find he sum of he decimal places (to the right) of the wo numbers 12.
5 and 35.
02 , which is here one plus two; that is three.
(3) Now write the result of step (1), count three decimal places from the left and place the decimal point at the start of the third figure, like that: 437 .
750
Justification Another way to present the solution
Find
: 12 .
5 35 .
02
Solution
: 12 .
5 35 .
02 125 10 3502 100 125 3502 1000 437750 1000 437 .
750 437 .
75
Division
Examples
Find
: 37 .
5 1 .
25
Solution
: 37 .
5 1 .
25 375 10 125 100 375 10 100 125 3 1 10 1 30 Example (1)
Example (2)
Find
: 0 .
375 1 .
25
Solution
: 0 .
375 1 .
25 375 1000 125 100 375 1000 100 125 3 10 1 1 3 10 0 .
3
Example (3)
Find
: 0 .
0375 12 .
5
Solution
: 0 .
0375 12 .
5 375 10000 125 10 375 10000 10 125 3 1000 1 1 3 1000 0 .
003
Example (4)
Find
: 1500 1 .
2
Solution
: 1500 1 .
2 1500 12 10 1500 10 12 500 10 4 5 ( 25 )( 10 ) 1250