Multiplying Decimals Worksheets

Teach the whole-number multiplication first, then show where the point goes and why it is not lined up like addition. Give the page for about twenty minutes. Students multiply as if there were no points, then place the decimal. With the answer key on, they can check the digits and the point separately. Repeat the same Factors setting across a few days before moving to the next one.

The new idea is point placement: count the decimal places in both factors, and the product has that many. Tenths times a whole number gives one place, hundredths times a whole number gives two, and tenths times tenths also gives two. Students often line up the points like in addition, which is wrong for multiplication. This builds on whole-number multiplication and decimal place value, and leads into dividing decimals.

Factors offers Tenths × whole, Hundredths × whole and Tenths × tenths, and the page opens on the middle one. Begin with Tenths × whole to build confidence, then move to Tenths × tenths for the full rule. The whole-number multipliers skip 0 and 1. Pick 12 problems for slower work and 30 for a longer practice block.

How do I know where the decimal point goes in the product?

Count the digits after the point in each factor and add them. Put that many places in the product, counting from the right. For 2.4 × 1.5 that is two places.

Why does the key leave off trailing zeros?

Once the point is placed, 2.5 × 4 is simply 10, not 10.0. A child who writes the extra zero has the right value, so treat it as optional.

Should I estimate first?

Yes, it is the best check. Round each factor, multiply, and see whether the answer is in the same area. If 2.4 × 1.5 came out much larger than 4, the estimate shows the point is misplaced.