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Metric Units of Mass. The Metric System of Measurements uses the mass units: gram (g), kilogram (kg), and tonne (t). The SI unit of mass is the kilogram (kg).

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Math 0300

Metric Units of Mass

Mass and weight are closely related. Weight is a measure of how strongly the earth is

pulling on an object. Therefore, an object’s weight is less in space than on earth’s surface.

However, the amount of material in the object, its mass, remains the same. On the

surface of the earth, mass and weight can be used interchangeably.

The basic unit of mass in the metric system is the gram. If a box that is 1 cm long on all

sides is filled with water; then the mass of water is 1 gram.

1gram = the mass of water in the box.

The units of mass in the metric system have the same prefixes as the units of length:

1 Kilogram (kg) = 1000 grams (g)

1 hectogram (hg) = 100 g

1 decagram (dag) = 10g

1 gram (g) = 1 g

1 decigram (dg) = 0.1 g

1 centigram (cg) = 0.01 g

1 milligram (mg) = 0.001 g

Conversion between units of mass in the metric system involves moving the decimal

point to the right or to the left. Listing the units in order from largest to smallest will

indicate how many places to move the decimal point and in which direction.

To convert 350 g to kilograms, first write the units in order from the largest to the

Kg hg dag g dg cg mg 3 positions

Converting g to kg requires moving 3 positions to the left. 3 places

324g = 0.324 kg

Move the decimal point the same number of places and in the same direction.

Example1 Example2

Convert 4.23 g to milligrams. Convert 42.3 mg to grams.

Solution Solution

4.23 g = 4230 mg 42.3 mg = 0.0423 g

Student Learning Assistance Center - San Antonio College 1

Metric Units of Mass

Mass and weight are closely related. Weight is a measure of how strongly the earth is

pulling on an object. Therefore, an object’s weight is less in space than on earth’s surface.

However, the amount of material in the object, its mass, remains the same. On the

surface of the earth, mass and weight can be used interchangeably.

The basic unit of mass in the metric system is the gram. If a box that is 1 cm long on all

sides is filled with water; then the mass of water is 1 gram.

1gram = the mass of water in the box.

The units of mass in the metric system have the same prefixes as the units of length:

1 Kilogram (kg) = 1000 grams (g)

1 hectogram (hg) = 100 g

1 decagram (dag) = 10g

1 gram (g) = 1 g

1 decigram (dg) = 0.1 g

1 centigram (cg) = 0.01 g

1 milligram (mg) = 0.001 g

Conversion between units of mass in the metric system involves moving the decimal

point to the right or to the left. Listing the units in order from largest to smallest will

indicate how many places to move the decimal point and in which direction.

To convert 350 g to kilograms, first write the units in order from the largest to the

Kg hg dag g dg cg mg 3 positions

Converting g to kg requires moving 3 positions to the left. 3 places

324g = 0.324 kg

Move the decimal point the same number of places and in the same direction.

Example1 Example2

Convert 4.23 g to milligrams. Convert 42.3 mg to grams.

Solution Solution

4.23 g = 4230 mg 42.3 mg = 0.0423 g

Student Learning Assistance Center - San Antonio College 1