1. Using the Metric System
Braintree High School

2. Identifying Appropriate Metric Measures
Type
Unit
Reference Examples
Length
Millimeter (mm)
Thickness of a dime
Centimeter (cm)
Width of a thumbnail
Kilometer (km)
Distance from doorknob to floor
Capacity
Milliliter (mL)
About 5 drops of water
Liter (L)
Quart of milk
Mass
Milligram (mg)
Mass of a speck of sawdust
Gram (g)
Mass of a paper clip
Kilogram (kg)
Half the mass of the math book.

3. Choose an appropriate metric unit.
Height of a classroom chalkboard?
Meter; the height of a chalkboard is about twice the distance from the floor to the doorknob.
Mass of a backpack filled with books?
Kilogram; a backpack with textbooks is many times the mass of our math book.
Capacity of a birdbath?
Liter; several quart bottles of water will fill a birdbath.

4. Choose an appropriate metric unit.
Length of a broom.
Centimeter. Meter could work but 2 meters is overkill for a broom. So centimeters will give us a more accurate measurement.
Mass of an candy bar.
Grams. A candy bar has a mass of several grams but is much less than 1 kilogram.
Mass of a horse.
Kilograms. A horse is very heavy, so grams are too small.
Capacity of a car’s gas tank.
Liter. A gas tank holds several liters, so milliliters are too small.

5. Choose a reasonable estimate. Explain.
Capacity of a juice box: 200 mL or 200 L?
200 mL: juice boxes hold less than a quart of milk.
Length of a new pencil: 15 cm or 15 m?
15 cm: the length of a pencil would be about 15 widths of a thumbnail.
Mass of a small tube of toothpaste: 100 g or 100 kg?
100 g: the mass is about the same as a box of paper clips.

6. Choose a reasonable estimate. Explain.
The distance between two cities: 50 mm or 50 km?
50 km, because a km is about one half of a mile.
Amount of liquid that an eyedropper holds: 10 mL or 10 L?
10 mL, 10 liters is what a gasoline tank would hold, 10 mL is only a few drops.

7. Converting Units
Metric system uses a decimal system to relate different units to each other.
You can convert from one unit to another by multiplying or dividing by 10, 100, 1000, and so on.
Names of units work on PREFIXES.
Milli-
Centi-
Deci-
UNIT
Deka-
Hecto-
Kilo-
.001
.01
.10 10
100
1000

8. Write in each unit with its prefix.
Milli-
Centi-
Deci-
UNIT
Deca-
Hecto-
Kilo-
Length
(mm)
(cm)
(dm)
Meter
(m)
(dam)
(hm)
(km)
Capacity
(mL)
(cL)
(dL)
Liter
(L)
(daL)
(hL)
(kL)
Mass
(mg)
(cg)
(dg)
Gram (g)
(dag)
(hg)
(kg)

9. Going From One Unit To Another
To convert from one unit to another in the metric system, find the relationship between the two units.
Is it length? Capacity (or volume)? Mass (weight)?
Multiply if you’re going from a large unit to small unit. There will be more smaller units than bigger units.
Divide if you’re going from a small unit to a large unit. There will be less bigger units than smaller units.

10. So lets try it… 4.35 L = ___ mL 4.35 L • 1,000 = 4,350
914 cm = ___ m
914 cm  100 = 9.14
914 cm = 9.14 m

11. Complete each statement.
35 mL = ___ L
35 mL  1000 = 0.035
35 mL = L
___ g = 250 kg
___ g = 250 kg • 1000
250,000 g = 250 kg
___ cm = 68 m
___ cm = 68 m • 100
6,800 cm = 68 m