### Multiply and divide decimals by powers of ten (by 10, 100, 1000 etc.)

In this video I show, first of all, the common shortcut: you move the decimal point in the number as many steps as there are zeros in the number 10, 100, 1000 etc. For example:

2.16 × 10,000 = 21,600.0

It is as if the point moved four steps from between 2 and 1 to between zeros.

You can see better examples of this in my lesson Multiply and Divide Decimals by 10, 100, and 100 at HomeschoolMath.net.

Then, I also show

Multiply & Divide Decimals by powers of ten

2.16 × 10,000 = 21,600.0

It is as if the point moved four steps from between 2 and 1 to between zeros.

You can see better examples of this in my lesson Multiply and Divide Decimals by 10, 100, and 100 at HomeschoolMath.net.

Then, I also show

*where this shortcut originates*, using PLACE VALUE charts. In reality, it's not the decimal point moving (it's sort of an illusion), but**the digits of the number move within the place value chart**(to the opposite direction from the way the decimal point seems to "move"). This explanation can really help students to understand the reason behind the "trick" of moving the decimal point.Multiply & Divide Decimals by powers of ten