Lesson 14 Choosing the Appropriate Unit

Here are some samples to remind you of the relative size of metric measurements

Length Millimeter (mm) – a very small distance or length; a dime is a millimeter thick.Millimeter (mm) – a very small distance or length; a dime is a millimeter thick. Centimeter (cm) – a little less than ½ inch. A nickel is about 2 centimeters wide. A computer screen would be measured in centimeters.Centimeter (cm) – a little less than ½ inch. A nickel is about 2 centimeters wide. A computer screen would be measured in centimeters. Meter (m) – a little more than a yard. The length of a field would be measured in meters.Meter (m) – a little more than a yard. The length of a field would be measured in meters. Kilometer (km) – more than ½ mile. Long distances such as the distance between two cities, are measured in kilometers.Kilometer (km) – more than ½ mile. Long distances such as the distance between two cities, are measured in kilometers.

Weight and Mass Milligram (mg) – a very small weight; used to weigh a small amount of powder.Milligram (mg) – a very small weight; used to weigh a small amount of powder. Gram (g) – about the weight of a paper clip.Gram (g) – about the weight of a paper clip. Kilogram (kg) – a little more than two pounds; the weight of a textbook.Kilogram (kg) – a little more than two pounds; the weight of a textbook.

Volume Milliliter (ml) – this is the same as a cubic centimeter.Milliliter (ml) – this is the same as a cubic centimeter. Liter (L) – a little more than a quart. Soda is sold in liter bottles.Liter (L) – a little more than a quart. Soda is sold in liter bottles.

Example 1 James wants to measure the distance from the road in front of his school to the football field in the back of the school. What metric unit would he most likely use?James wants to measure the distance from the road in front of his school to the football field in the back of the school. What metric unit would he most likely use? Strategy: Look in the length category where there are four units to choose from, millimeter, centimeter, meter, and kilometer. Millimeter and centimeter are too small; kilometer is too long.Strategy: Look in the length category where there are four units to choose from, millimeter, centimeter, meter, and kilometer. Millimeter and centimeter are too small; kilometer is too long.

Solution The most appropriate unit for James to use is the meter.The most appropriate unit for James to use is the meter.