Measuring Length

You can measure the length of ANYTHING! When we measure length we measure how long something is.

We measure using units of length. These can be non-standard units………..

……..…or standard units. Millimetres (mm) Centimetres (cm) Metres (m) Kilometres (km)

Comparing units of length

Measuring Length in Centimeters The centimeter (cm) is used to measure lengths in the metric system. A smaller unit, the millimeter (mm) is used for more accurate measurements. How long is the paper clip to the neatrest centimeter?

DEVELOPING THE CONCEPT We are looking for the length of the pen to the nearest _____________. The millimeter lines help us determine whether the pen is closer to ____ or _____ centimeters.

If the pen is less than 5 millimeters from the 3 centimeter line, round down. Round up to the next higher centimeter if the paper clip is 5 millimeters or more from the 3-centimeter line. Since the pen is _____ millimeters longer than the 3- centimeter line, we say that it is ____ centimeters long, to the nearest centimeter. Solution sentence: _____________________________

PRACTICE Measure each item to the nearest centimeter.

Circle the best estimate: -The width of a fingernail a. 10mm b. 100mm c. 10cm -The height of a chair. a. 45mm b. 45cm c. 450 cm -The width of this page. a. 22mm b. 22cm c. 220cm -The width of a dime. a. 18mm b. 180mm c. 180 cm