Chapter 3 · Decimals and percents · page 14 of 68
Multiplying decimals
levelPre-algebra
standard6.NS.B.3
practiceDecimals and percents
Multiply as if there were no decimal points, then count. The product has as many decimal places as the two factors have together.
How to use it
- Ignore the points and multiply the whole numbers.
- Count the decimal places in both factors and add the counts.
- Put that many decimal places in the answer, adding zeros on the left if needed.
Example
Where it goes wrong
- Lining up the points as in addition. Multiplication does not line up anything.
- Counting one place when each factor has one: 0.4 × 0.3 is 0.12, not 1.2.