In problems which
involve measurements such as width, length, height, weight,
capacity or temperature, it is often necessary to convert
from one measurement unit to another.
For example, let's say you were going to purchase a new
carpet for your bedroom. First you would get out your tape
measure, or yardstick, and measure the length and width of
the room. This would probably be done in feet and
inches. Then you would take these measurements to the
store and "OUCH" you see that all of the carpeting in the
store is being sold by the "square yard!" Being unable
to convert the feet and inches measurements into square
yards means that you really don't know whether you are
getting the best deal for your money.
Hopefully after working through this lesson you will better
understand how important this skill is, and how often this
type of "math" gets into your everyday life.
To convert from a LARGER unit to a SMALLER unit...MULTIPLY
convert from a SMALLER unit to a LARGER unit...DIVIDE
Complicating matters a bit is the fact that in the United States
we have two different sets of measurement units.
Our basic system is the "customary"
or "English" system. In
this system units include: inch, foot, yard, mile, ounce,
pound, pint, quart, gallon and the Fahrenheit scale for
However, as we do
business in the global community,
the metric system is also a
necessary system to understand.
This system uses units such as: meter, centimeter,
kilometer, gram, kilogram, liter, milliliter
and the Celsius scale for temperature.
In this lesson you will see
conversions in both of these systems. However, this is NOT
a lesson on either the English or Metric system, but rather this
is an explanation of how to convert from one unit to another
unit within the same system.
Let's start with
an easy example.
Shack uses 37 quarts of tomato sauce every day.
How many gallons do they use?
1 gallon = 4 quarts
We are converting from a smaller unit (quart) to a larger unit
(gallon). So we DIVIDE!
(37)/(4) = 9 with 1 quart left over.
37 quarts = 9 gal.1 qt.
4 boards measure; 21", 19",
33" and 43" respectively. If boards come in 8', 10', and 12'
lengths, what length board should we buy so that the least
scrap is left?
First we need to add the
lengths of the boards together:
21 + 19 + 33 +43
Next we will convert the 8',10' and 12' lengths to inches.
We are converting from a larger unit to a smaller unit...so we must
Conversion factor: 1 foot = 12 inches
(8)(12) = 96
(10)(12) = 120
(12)(12) = 144
We need 116 total inches...so the best buy is
the 10' (120") length. There will only be 4 inches of scrap.
Now let's look
There are 720 centimeters of tape on a roll. How many
meters of tape is this?
Conversion factor: 1 meter = 100 centimeters
We are converting from a smaller unit to a large unit...so we
720 centimeters is the same as 7.2 meters!