Since decimal numbers are base ten numbers, multiplication of decimals is similar to multiplication of whole numbers. However when multiplying decimals there is one additional step we must determine where to write the decimal point in the product.
It is important to focus how many decimal places there are in each decimal being multiplied.
Multiply the decimals as if they were whole numbers.
Find the total number of decimal places in both factors.
Insert a decimal point in the result from step 1 so that the answer has the same number of decimal places as the total found in step 2.
Multiply 5.9 $\times$ 3.4
We will ignore teh decimal points and mutiply 5.9 and 3.4 as if they were whole numbers. Then we will write a decimal point in that result so that the final answer has two decimal places.
Since the factor 5.9 has 1 decimal place and the factor 3.4 has 1 decimal place the product should have 1 + 1 = 2 decimal places.
5.9 $\times$ 3.4
Move 2 places from the right to the left and insert a decimal point in the answer.
Thus the answer for 5.9 $\times$ 3.4 is 20.06
Multiply 1.3 $\times$ (0.005)
We will ignore the decimal points and multiply 1.3 and 0.005 as if they were whole numbers. Tehn we will write a decimal point in that result so that the final answer has four decimal places.
Since the factor 1.3 has 1 decimal place, and the factor 0.005 has 3 decimal places the product should have 1 + 3 = 4 decimal places.
1.3 $\times$ 0.005
Write 2 placeholder zeros in front of 6. Then move 4 places from the right to the left and insert a decimal points in the answer.
Thus the answer for 1.3 $\times$ 0.005 is 0.0065