Multiply Decimals

Multiplying decimals is relatively easy if you follow these 3 simple steps:

1) Take out the decimal points;

2) Calculate the multiplication sum as usual with whole numbers;

3) Put the decimal points back in.

e.g. 8.6 x 4

Step 1: Take out the decimal point, so we now have 86 x 4

Step 2: Complete the multiplication sum as usual, 86 x 4 = 344

Step 3: If you look at the original question, we had one number after the decimal point (8.6 x 4) so we must have one number after the decimal point in the answer, so 8.6 x 4 = 34.4

e.g. 3.2 x 5.6

Step 1: Take out the decimal point, so we now have 32 x 56

Step 2: Complete the multiplication sum as usual, 32 x 56 = 1792

Step 3: If you look at the original question, we had two numbers after the decimal point (3.2 x 5.6) so we must have two numbers after the decimal point in the answer, so 3.2 x 5.6 = 17.92

In this activity, you will need to calculate the product when multiplying decimals by both whole numbers or another decimal. 

You should follow the three steps described above, taking out the decimal point and then re-inserting it after you have calculated the multiplication sum as usual.