skill focus fractions, decimals & percentages...percentages percentages refer to fractions of a...
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Skill Focus
Fractions,
Decimals &
Percentages Certificate I
Access to Work & Training
NSWTAFE New England
Institute
The Relationship Among
Fractions, Decimals, Percents:
All represent a part of a whole A fraction is based on the number into which the whole is
divided (the denominator). The numerator (the top) is the PART, the denominator (the bottom) is the WHOLE.
A decimal is based on the number in terms of tenths,
hundredths, thousandths, etc.
A percent is based on the number in terms of 100.
Example:
How do we get
from one form to another?
1. Fraction to Decimal
Divide the denominator (the bottom of the fraction) into the numerator (the top of the fraction).
Place a decimal point after the number inside the division
"box" and attach as many zeros as necessary to handle the
division.
If the quotient does not come out evenly,
follow any rounding instructions.
How do we get
from one form to another?
2. Decimal to Percent
Move the decimal point two places to the right (this
multiplies the number by 100).
. 5 0 = 50%
OROR 0.50 x 100 = 50.0 Attach the percent sign: 50%
How do we get
from one form to another?
3. Percent to Decimal
Move the decimal point two places to the left
(this divides the number by 100).
5 0 % = .50
How do we get
from one form to another?
4. Percent to Fraction
Place the number in the percent over 100 and
reduce.
How do we get
from one form to another?
5. Fraction to Percent
Multiply the fraction by 100, reduce, and attach a
percent sign.
How do we get
from one form to another?
6. Decimal to Fraction
You will be using place value to do this one!
Count the decimal places of the decimal starting from the
decimal point.
If there is one decimal place, place the number over 10 and reduce. If there are two decimal places, place the number
over 100 and reduce. If there are three decimal places,
place the number over 1000 and reduce. And so on ….
Percentages
Percentages refer to fractions of a whole;
that is, whatever you're looking at, the percentage is how much of the
whole thing you have.
For instance, 50% means 1/2 ; 25% means 1/4 ; 40% means 2/5
Often you will need to figure out what percentage of something another thing is.
For example: For example: if a class has 26 students, and 14 are female, what percentage of the students are female?
It is 14 out of 26, or 14/26 = 0.538461538462..., or about 54%.
Per cent
"Percent" is actually "per cent", meaning "out of a hundred".
(It comes from the Latin per centum for "thoroughly hundred".)
You can use this "out of a hundred" meaning, along with the fact that
fractions indicate division, to convert between fractions, percents, and
decimals.
What does % mean in
everyday life?
We use percentages to
describe fractions.
Percentages mean more to us
than fractions We quite freely use the
term “percent” to describe a portion but seem to stumble
with a decimal amount or fraction.
Decimal to Percent
DecimalDecimal--toto--percent conversions are simple:percent conversions are simple: just move the decimal point two places to the right.
(Remember, $0.50 is one-half, or 50%, of a dollar.)
For exampleFor example:
0.23 = 23% 0.23 = 23%
2.34 = 234% 2.34 = 234%
0.0097 = 0.97% 0.0097 = 0.97%
(Note that 0.97% is less than one percent.
It should not be confused with 97%, which is 0.97 as a decimal.)
Fraction to Percent
This conversion starts the same as the previous one, but the final answer
can come in a couple different formats sometimes.
You always start by doing the division (fractions are division,
remember!), and then (usually) you move the decimal point two places
to the right.
ExampleExample:
Table
of
Common
Fractions
and their
Percentage
Equivalents
Table of
Common
Fractions and
their Decimal
Equivalents or
Approximations
Remember:Remember:
Always show your working:
It keeps your thinking
methodical and gives you
a chance to find if and
where you made a
mistake.
http://www.tc3.edu/instruct/sbrown/stat/showwork.htm
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