A ruler is a tool you can use to measure how long something is. A ruler has number labels. The first number is 0. You measure the length of an object by lining up one side of your object with the 0. Then see where the other end of the object lines up on the ruler.

**To better understand measuring & adding length…**

## LET’S BREAK IT DOWN!

### Measure spaceships using paper clips.

You can use everyday objects to measure length. You want to know the length of your toy spaceship. You put one paper clip at the left end of your spaceship. Then you line up more paper clips next to the first and count the number of paper clips from one end to the other. The spaceship is 9 paperclips long.

### Compare the lengths of spaceships.

Your friend has a toy spaceship that is 7 paper clips long. How much longer is your spaceship than your friend's? 9 – 7 = 2. Your spaceship is 2 paper clips longer than your friend’s.

### Use a ruler to measure toy trains.

The numbers on a ruler show equal-sized parts, like your equal-sized paper clips. A ruler is an easier way to measure! This ruler measures in inches. To measure your toy train, you can line up the 0 mark of the ruler at the left end of the train. The right end of the train stops closest to the number 7. The train is 7 inches long.

### Use a yardstick to measure toy firetrucks.

A yardstick is a bigger measuring tool. It can measure up to 36 inches. It also has other measurements, like 1 foot. You can use a yardstick to measure your toy firetruck. Line up the 0 mark with the left end of the firetruck. The right end of the firetruck stops near 24 inches. The firetruck is 24 inches long. The yardstick has another label at the same mark, so the firetruck is also 2 feet long.

### Measure and compare bridges.

You built a bridge that is 20 inches long. Your friend built a bridge that is 16 inches long. How much longer is your bridge? 20 – 16 = 4. Your bridge is 4 inches longer. How long are your bridges together? 20 + 16 = 36. Together, the bridges are 36 inches long.