10 % of 40? (explain please!)

2 Answers
smendyka
Mar 6, 2018

See a solution process below:

Explanation:

"Percent" or "%" means "out of 100" or "per 100", Therefore 10% can be written as #10/100#.

When dealing with percents the word "of" means "times" or "to multiply".

Finally, lets call the number we are looking for "n".

Putting this altogether we can write this equation and solve for #n# while keeping the equation balanced:

#n = 10/100 xx 40#

#n = 400/100#

#n = 4#

Cameron · EZ as pi
Mar 6, 2018

#4#

Explanation:

#10%# can be written as #10/100 or 1/10 or 0.1#

When asked to find #10%# you simply multiply the number by
#0.1 or 1/10.# which is the same as dividing by #10#

If you don't have a calculator you can simply divide by #10# by taking off a zero or move the decimal point one place to the left.

e.g #10 % " of " 20# take off the #0# to get #2.#
e.g #10% " of " 30# take off the #0# to get #3#.

Therefore #10% " of " 40# you take off the #0# and get #4#.

You can prove this as #40xx0.1=4#

In a more complicated example, #10%" of " 55# you would have to move the decimal point. #55# can also be written as #55.0# so the answer would be #5.5#

Hope this was helpful

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