Elementary Test Prep: Math 4 Test (Grades 3-4) Metric system

Lesson Page Measurement

The metric system is another system of measurement used to describe an object's length, mass, or volume. It uses one base unit and adds prefixes. The metric system uses the powers of ten as the conversion factors from unit to unit.

Metric Units of Length
Kilometer (km)	1 km = 1,000 m	A kilometer is about the length of 100 school buses lined up end to end.
Meter (m)	1 m = 100 cm	A meter is about half the height of a door.
Decimeter (dm)	1 dm = 10 cm	A decimeter is about the width of your teacher's hand.
Centimeter (cm)	1 cm = 10 mm	A centimeter is about the width of a pencil.

The area of a figure is the number of square units needed to cover it.

Count the number of square units to find the area.	Area = 8 square cm
You can also find the area of a rectangle by using a formula. Area = length x width	Area = 2 x 4 Area = 8 square cm

Perimeter is the word used to describe the distance around the outside of an object or shape. To find the perimeter of any shape, add the lengths of its sides.
	When two pairs of sides are the same length, multiply 2 times the length and 2 times the width. Then add the products.
( 2 x 9 m ) + ( 2 x 5 m ) =	Perimeter: 18 m + 10 m = 28 m
	When all the sides are the same length, multiply the number of sides times the length of one side.
4 sides x 5 cm	Perimeter 4 x 5 = 20 cm
	When the lengths of the sides are different, add the lengths of the sides.
5cm + 5cm + 4cm + 8cm + 4cm =	Perimeter: 26 cm

The Volume of a solid is the number of cubic units it contains.
	This is one cubic unit
Find the cubic measure by counting the cubes.
	10 cubic units
You can also find the volume of a rectangular prism by using a formula.
Volume = length x width x height

	Volume = 3 cm x 2 cm x 5 cm Volume = 30 cubic cm

Let's Practice!
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Remember:
Use square units, a 2-dimensional measure, to talk about area.

Use cubic units, a 3-dimensional measure, to talk about volume.