Multiplying and Dividing by Powers of Ten

Last week, 5th grade math classes were using this place value chart to help them think about and find patterns.

We started by dividing by ten. Using the chart, we realized that if you have 1 group of millions it was easier to divide if you regrouped the million into 10 one hundred thousands. From there it was easy to divide by ten!

We did something similar with multiplication. Before long students were seeing a pattern.

When you move the decimal point to the right you are multiplying by a power of 10. If you move it to the right two places, you are multiplying by 2 powers of ten (or 100), etc

If you move the decimal to the left, you are dividing by a power of ten. If you move to the decimal to the left two places, you are dividing by 2 powers of ten (or 100), etc

Have a Mathematical Week!