Multiplication of decimal numbers is similar to whole number multiplication.
Rules for Decimal Multiplication
First we multiply the decimal numbers as if they were whole numbers by ignoring the decimal points.
Here the decimal points are not lined up vertically as in addition and subtraction. Here the digits are lined up to the right.
The number of digits after the decimal point in both the numbers are counted and added.
In the final product, a decimal point is placed before that many digits from the right.
Multiply 2.004 × 2.3
Step 1:
2.004 × 2.3
Here the digits are lined up to the right
We now multiply the numbers by ignoring the decimal points and assuming as if they were whole numbers.
Step 2:
2.004 has three decimal places. 2.3 has one decimal place. So the product of these numbers has four decimal places.
Multiply 3.002 × 4.5
Step 1:
3.002 × 4.5
Here the digits are lined up to the right
We now multiply the numbers by ignoring the decimal points and assuming as if they were whole numbers.
Step 2:
3.002 has three decimal places. 4.5 has one decimal place. So the product of these numbers has four decimal places.