know from lesson 340
A history of Percents, the word "percent"
originally meant "cents", and was used back in the
dark ages by merchant to remove evil spirits form numbers.
since a % sign is nothing more than an 'evil spirit remover',
we must convert any % numbers into either decimals or fractions
before we can use them.
TO WRITE A PERCENT AS A DECIMAL:
the word "percent" originally meant "cents",
changing a percent to a decimal is easy; just write it as
money in dollar notation, and then remove the dollar sign.
look at a few:
- 35% or 35 cents
= $.35 or 0.35 (Some people
put the zero in front of the decimal to draw attention to
or 8 cents = $.08 or 0.08
or 150 cents = $1.50 or 1.50=1.5
(Remember the zero in the
hundredths spot of the decimal can be dropped without changing
that in every case
the decimal notation places the decimal point 2
spots to the LEFT of the % notation.
actually ALWAYS HAPPENS. To change a % to a decimal, simply
drop the percent sign and move the decimal two spots left.
If you don't see any decimal point on a percent number,
like in the examples above, remember that it is always to
the right of the one's place. For example, 35%=35.%.
look at a few harder ones:
- 3.5% or 3.5
cents = $.035 or 0.035
- .5% or .5 cents
or half a cent =$.005 or 0.005
- 4,521% or 4521
cents = $45.21 0r 45.21
- 68 3/5%
or 68.6 cents* = $.686
*Notice that above 3/5 =.6,
so we just changed the original % to a decimal before getting
TO WRITE A PERCENT AS A FRACTION:
Now that you can
write percents as decimals, to get the fraction you simply
say the decimal formally.
- 35% =
0.35 which is read, "thirty-five hundredths",
so we write the fraction 35/100. Now this will reduce to
7/20, so 35% = 7/20.
=7.52 which is read, "seven and fifty-two hundredths",
so we write the mixed number 7 52/100.
This will reduce to 7 13/25.
- .24% =
0.0024 which is read,
"twenty-four ten-thousandths", so we write the
24/10,000. This fraction reduces to 3/1,250.