Moving decimals is an easy method of multiplying numbers containing two numerals after a decimal, with a check at the end to ensure that the decimals are properly placed after the multiplication process is complete. All that's required is ignoring decimal placement when solving the problem and then determining just where the decimal should be returned after completion.
- Remove the decimals
Remove the decimals completely from numbers with two numerals after the decimal point in order to multiply the two numbers together. An example of a number requiring the removal of two decimal places is 23.45. After removing the decimal, you would have 2345 to multiply.
- Multiply the adjusted number
Multiply the adjusted number without the decimals by the second number in the problem. For example, 2345 x 2. The product of the multiplication problem is 4688.
- Move the decimal back into place
Replace the decimal in the answer by counting two positions from the end of the number and placing the decimal back into the number. If the number is 4688, for example, the decimal should be placed before the eight, making the number 46.88.
- Check the answer
Check that the decimal placement is correct by counting the number of positions in the original numbers behind the decimal. The new product of the two multiplied numbers should have the same number of positions behind the decimal as the original numbers. If a whole number is multiplied by a number with two positions behind the decimal, then the result should have two numbers behind the decimal as well.