Page 21 - Arithmetic

Decimals
A decimal is a number which represents the whole part and fractional part separated by a point. The point is called the decimal point.
Converting decimal to fraction
All the numbers to the right of the decimal point are fractions with denominators of 10, 100, 1000, 10000, etc.
For example, 0.5 = 5 = 1 10 2
Adding and subtracting decimals
Adding and subtracting decimals is similar to whole numbers. After performing the operation, place the decimal point at the appropriate place.
Worked Example 11
Convert 0.75 to the equivalent fraction.
Solution:
0.75= 75 =3 100 4
Worked Example 12
Subtract 4.65 – 3.08
Solution:
Consider the figure as 465 – 308 = 157
Place the decimal point 2 places after 1. So, the answer is 1.57
Multiplying decimals
Multiply like whole numbers and count the number of digits after the decimal point in each number. In the answer, place the same number of digits to the right of the decimal point.
Worked Example 13
Multiply 3.1 and 5.5
Solution:
31 × 55 = 1705
The number of digits to the right of the decimal point in the number is 2. So, place the decimal point such that two digits are to the right of the decimal point.
So, the answer is 17.05
Page 20 of 55
Arithmetic Concept