# 3rd Grade Math Review: Day 11

In __yesterday's post__ we reviewed spent a little time looking at how to find the area of a rectangle and what that measurement represents. Today we look at a related concept, perimeter, and also explore the trick of calculating intervals of time.

**Perimeter**

Don't get confused with area and perimeter. While are area looks at the amount of space within an object, perimeter finds the distance around it. Here's a video explaining the difference.

Try to solve these problems to test your new knowledge.

**Intervals of Time**

Not to be confused with elapsed time, something that students learn in 4th grade, intervals of time is the beginning of understanding how adding and subtracting time works.

Here's a deceptively simple problem from a released STAAR test to practice on.

**Correct Answers**

Here's a quick video showing how to solve each problem.