- Basic operations on decimals are performed in the same way as basic operations are performed on the whole numbers.
- To add or subtract decimals, we align the decimal points of given numbers and perform the operation. In the sum or difference, we mark decimal point in the column of decimal points.
- If the decimals are of different decimal places, we convert them into same decimal places by putting zeros at the right of the decimals wherever necessary.
- To multiply two decimals, we multiply them as whole numbers ignoring the decimal points. We insert the decimal point in the product by counting as many places from right to left as the sum of number of decimal places of the given decimals.
- To multiply a decimal by 10, 100 or 1000, we simply shift the decimal point in the given number from left to right.
- one place, if it is multiplied by 10
- two places, if it is multiplied by 100
- three places, if it is multiplied by 1000 and so on.
- In division of decimals we proceed as:
- Decimal ÷ Whole Number (other than zero):
We first divide the whole number part of the dividend and then move towards decimal
part of dividend. Correspondingly, we mark decimal point in the quotient also and then continue division as usual.
- Whole Number ÷ Decimal:
We first remove the decimal point from the denominator by multiplying both numerator and denominator with 10, 100 or 1000 etc. We perform the operation of division as usual.
- Decimal ÷ Decimal:
We first remove the decimal point from the denominator and perform division operation as usual.
- Whole Number ÷ Whole Number (other than zero):
When the divisor is
greater than the dividend we mark a decimal point in both the
quotient and dividend and continue the division.
- Decimal ÷ 10 or 100 or 1000:
We simply move the decimal point in the
dividend to the left by:
- one place if it is divided by 10
- two places if it is divided by 100
- three places if it is divided by 1000 and so on.
Directions: Answer the following questions. Also write at least 5 examples of your own for each of decimal operations.