When multiplying decimals where do you move the decimal?

Answer 1

the answer is it stays in the same place.

* * * * *

Not quite.

Suppose you want to multiply two decimal numbers A and B. Multiply the two numbers ignoring the decimal points.

Count the number of digits after the decimal point in the number A.

Count the number of digits after the decimal point in the number B.

Add these two numbers together. This is the number of digits you want after the decimal point in the answer. So count back from the end.

Example:

2.54 * 3.5 (this is number of centimetres in 3.5 inches)

254*35 = 8890

Number of digits after the decimal point in 2.54 is 2 (5 and 4).

Number of digits after the decimal point in 3.5 is 1 (5).

2 + 1 = 3 so there must be 3 digits after the decimal point in the answer.

Therefore 8890 becomes 8.890

NOW, you can simplify it to 8.89