Warm up p 211 # 43-46

Additional 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.

Check It Out: Example 1 Choose the most appropriate metric unit for each measurement. Justify your answer. A. The amount of liquid in 10 teardrops B. The mass of a pencil eraser C. The length of 15 soccer fields Milliliters—The amount of liquid in 10 teardrops is similar to the amount of liquid in several eyedroppers. Grams—The mass of a pencil eraser is similar to the mass of a few paperclips. Kilometers—The length of 15 soccer fields is similar to the length of 10 football fields.

Reading Math Prefixes: Milli- means “thousandth” Centi- means “hundredth” Kilo- means “thousand”

To convert metric units, multiply or divide by a power of 10 To convert metric units, multiply or divide by a power of 10. Multiply to convert to a smaller unit and divide to convert to a larger unit.

Additional 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: 530. = 5.3 L

Additional Example 2B: Converting Metric Units Convert the measure. 1,070 g to milligrams 1 g = 1000 mg, so multiply by 1000. 1,070 g = (1070  1000) mg Move the decimal point 3 places right: 1,070,000. = 1,070,000 mg

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: 980. = 98 m

Check It Out: Example 2B 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. = 58,000 cg

Additional Example 3: Using Unit Conversion t to Make Comparisons Elizabeth purchases one pumpkin that weighs 3 kg and another that weighs 2,150 g. Which pumpkin weighs more? Use estimation to explain why your answer makes sense. You can convert the mass of Elizabeth’s pumpkin to grams. 1 kg = 1000 g, so multiply by 1,000. 3 kg = (3  1,000) g Move the decimal point 3 places right: 3.000. = 3,000 g 2,150 g is about 2 kg. Since 2 kg < 3 kg, Elizabeth’s 3 kg pumpkin weighs more.

Check It Out: Additional Example 3 Tyesha purchases a bag of potatoes that weighs 2.5 kg and another bag that weighs 3,850 g. Which bag weighs more? Use estimation to explain why your answer makes sense. 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 x 1,000) g Move the decimal point 3 places right: 2.500. = 2,500 g 3,850 g is about 4 kg. Since 4 kg > 2.5 kg, Tyesha’s 3,850 g bag weighs more.

Lesson Quiz 1. 1,270 g to kilograms 2. 890 cm to millimeters 1.27 kg Convert each measure. 1. 1,270 g to kilograms 2. 890 cm to millimeters 3. 750 mL to liters 4. 122 km to meters 5. 800 mg to grams 1.27 kg 8,900 mm 0.75 L 122,000 m 0.8 g 6. Rosa walks 1.5 km to the library. Meghan walks 2,200 m to the library. Who walks farther? Use estimation to explain why your answer makes sense. Meghan; 0.7 km