1. AF2. 1 Convert one unit of measurement to another (e. g
AF2.1 Convert one unit of measurement to another (e.g., from feet to miles, from centimeters to inches).
California
Standards

2. Write this at the top of your paper
You can use the following benchmarks to help you understand millimeters, grams, and other metric units.
Write this at the top of your paper

3. Example 1: Choosing the Appropriate Metric Unit
Choose the most appropriate metric unit for each measurement. Justify your answer.
A. The amount of water a runner drinks each day
Liters—The amount of water a runner drinks each day is similar to the amount of water in a large water bottle.
B. The length of a boat
Meters—The length of a boat is similar to the length of several doorways.
C. The mass of a car
Kilograms—The mass of a car is similar to the mass of several hundred textbooks.

4. Write this at the bottom of page 103.
The prefixes of metric units correlate to place values in the base-10 number system. The table shows how metric units are based on powers of 10.
Write this at the bottom of page 103.
You can convert units within the metric system by multiplying or dividing by powers of 10. To convert to a smaller unit, you must multiply. To convert to a larger unit, you must divide.

5. Example 2A: Converting Metric Units
Convert the measure.
530 cL to liters
100 cL = 1L, so divide by 100.
530 cL = (530 ÷ 100) L
Move the decimal point 2 places left: 5.30.
= 5.3 L

6. Example 2B: Converting Metric Units
Convert the measure.
1,070 g to milligrams
1 g = 1000 mg, so multiply by 1000.
1,070 g = (1,070  1,000) mg
Move the decimal point 3 places right: 1,
= 1,070,000 mg

7. Check It Out! Example 2A
Convert the measure.
980 dm to meters
10 dm = 1m, so divide by 10.
980 dm = (980 ÷ 10) m
Move the decimal point 1 place left: 98.0.
= 98 m

8. Example 3: Using Unit Conversion to Make Comparisons
Eliza buys one pumpkin that has a mass of 3 kg and another that that has a mass of 2,150 g. Which pumpkin has the greater mass? Use estimation to explain why your answer makes sense.
Convert 2,150 g to kilograms.
1,000 g = 1 kg, so divide by 1,000.
2,150 g = (2,150 ÷ 1,000) kg
= kg
Move the decimal point 3 places to the left.
The 3 kg pumpkin has the greater mass.
Check
Round 2,150 to the nearest thousand.
2,150 g is about 2,000 g or 2 kg
3 kg > 2 kg, so the answer makes sense.

9. Additional Example 3 Continued
Eliza buys one pumpkin that has a mass of 3 kg and another that that has a mass of 2,150 g. Which pumpkin has the greater mass? Use estimation to explain why your answer makes sense.
Check
Use number sense. There are 1,000 grams in a kilogram, so the mass of the other pumpkin is about 2,000 g or 2 kg. 3 kg > 2 kg, so the answer is reasonable.

10. Check It Out! Example 1
Choose the most appropriate metric unit for the measurement. Justify your answer.
The amount of liquid in 10 teardrops
Milliliters—The amount of liquid in 10 teardrops is similar to the amount of liquid in several eyedroppers.

11. Check It Out! Example 2
Convert the measure.
580 g to centigrams
1 g = 100 cg, so multiply by 100.
580 g = (580  100) cg
Move the decimal point 2 places right:
= 58,000 cg

12. Check It Out! Example 3
Tyesha purchases a bag of potatoes that has a mass of 2.5 kg and Casey purchases a bag with a mass of 3,850 g. Which bag of potatoes has the greater mass?
You can convert the mass of Tyesha’s bag to grams.
1 kg = 1000 g, so multiply by 1,000.
2.5 kg = (2.5  1,000) g
Move the decimal point 3 places right:
= 2,500 g
Tyesha’s 2,500 g bag of potatoes has a smaller mass.

13. Check It Out! Example 3 Continued
Tyesha purchases a bag of potatoes that has a mass of 2.5 kg and Casey purchases a bag with a mass of 3,850 g. Which bag of potatoes has the greater mass?
Check
3,850 g is about 4000 g or 4 kg. 4 kg > 2.5 kg, so the answer is reasonable.