90% of 95.6 is what?

2 Answers
Apr 27, 2017

=86.04

Explanation:

95.6 times0.9

=86.04

Apr 27, 2017

86.04

Explanation:

color(blue)("Preamble about percentages")

Basically percentage is just a fraction. It is a special one in that the bottom number (denominator) is fixed at 100.

The symbol % is a sort of unit of measurement but one that is worth 1/100

So as an example: 20% " "->" "20xx%" "->" "20xx1/100" "->" "20/100
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color(blue)("Answering your question")

In mathematics the word 'of' in 90% of 95.6 is the same as multiply. So we have:

90%" of "95.6" " ->" "90%xx95.6

But 90% is the same as 90/100 so we have:

90/100xx95.6

" "color(green)(ul(bar(|color(white)(2/2)"Using a calculator I get 86.04 "|))

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color(blue)("Additional teaching")

color(brown)("Suppose you do not have a calculator to hand. let me show you a")color(brown)("sort of cheat method to make the manual calculations easier.")

color(purple)("Doing the preparation")
Once used to this you would do it in 1 line

Consider the 90/100 -=(90-:10)/(100-:10)=9/10=9xx1/10

So we can write 90/100xx95.6" " as " "1/10xx9xx95.6

Do not like decimals so lets get rid of them in 95.6

95.6" is the same as "956xx1/10

So putting all this together we have:

1/10xx9xx956xx1/10

1/100xx9xx956
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color(purple)("Doing the calculation")
956
ul(color(white)(95)9) larr" Multiply"
8604

Now we deal with the 1/100

1/100xx8604 = 86.04

" "color(green)(ul(bar(|color(white)(2/2)"Calculating manually I get 86.04 "|))