Decimal Fractions Complete Tutorial
30-07-2023 All India Study Material
What are Decimal Fractions?
Decimal fractions are numbers that include a decimal point, representing a part of a whole number.
They are also known as decimal numbers and are used to express quantities that are not whole numbers.
A number in the form of X/Y where Y 
0 is known as fraction.
where X= Numerator and Y = Denominator.
Fraction = Numerator/Denominator
Example: 0.5, 1.25, 3.75, 8.9, etc.
Converting Decimal to Fraction: To convert a decimal fraction to a regular fraction,
follow these steps:
- Write the decimal as the numerator.
- Put the appropriate power of 10 as the denominator.
Example: Convert 0.75 to a fraction. 0.75 = 75/100 = 3/4
Converting Fraction to Decimal: To convert a fraction to a decimal, perform the division to get the decimal equivalent.
Example: Convert 5/8 to a decimal. 5 ÷ 8 = 0.625
Multiplying and Dividing Decimal Fractions:
a) Multiplication: Treat the decimals as whole numbers, ignoring the decimal point. Count the total number of decimal places in the given numbers and place the decimal point in the product accordingly.
Example: 1.5 * 2.4 = 3.6 (1 decimal place + 1 decimal place = 2 decimal places)
b) Division: Move the decimal point in the divisor and dividend to make the divisor a whole number. Then, divide as usual.
Example: 0.6 ÷ 0.2 = 3 (move decimal in 0.6 once to make it 6, and 6 ÷ 2 = 3)
Tricks for Quick Calculations:
- Approximation: In multiple-choice questions, you can use approximation techniques to quickly arrive at the closest answer without performing precise calculations.
- Rounding Off: Round off decimal numbers to the nearest whole number or decimal place to simplify calculations.
Sample Questions:
-
Calculate 3.75 * 2.4.
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Convert 0.625 to a fraction.
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Divide 3.142 by 0.2.
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Round off 8.978 to the nearest tenth.
Trick: To check if a decimal is divisible by 3, add all the digits. If the sum is divisible by 3, the decimal is also divisible by 3.
