Welcome to Percent Decrease with Mr. J! Need help with percent of change? You're in the right place!
Whether you're just starting out, or need a quick refresher, this is the video for you if you're looking for help with how to find percent of change (percent decrease). Mr. J will go through percentage decrease examples and explain the steps of how to calculate percentage decrease.
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Hopefully this video is what you're looking for when it comes to calculating percentage decrease.
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welcome to math with mr j
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in this video i'm going to cover percent
of change
and specifically percentage decrease we
have two examples that we're going to go
through together
in order to get this down now when we
calculate a percent of change
we need to find the amount of change so
the new number
minus the old number then we divide by
the
old number lastly we multiply by 100
so when we do the amount of change
divided by the old number
we're going to get a decimal we multiply
by 100
to convert that decimal to a percent so
let's jump into number one
where we have 16 to 19.
so we start with a 16 and now we have a
9
so we can see that we have a decrease
there
we need to see what percent of change
we're working with
when we go from 16 to 9. so let's plug
in
our numbers and the first thing we need
to do is figure out
the amount of change so the new number
minus the old
the new number is nine minus the old
which is 16. that's going to give us
negative 7 and we got a negative number
because we started with 16 and now we
have a 9
so that negative represents a decrease
let's divide by the old number which is
16.
and we need to multiply that by 100
so negative 7 divided by 16
that's going to give us negative
4000 three hundred seventy-five
ten thousandths and we multiply that by
one hundred
before i do that i do wanna mention that
you have to make sure
to always divide by the old or
original number because that's the
number that changed
so we want the percentage change
relative to the number we started with
we're looking at the percent that that
number changed
all right let's multiply by 100 now when
we multiply a decimal by 100
we can just move the decimal twice to
the right
so one two
and we end up with an answer of negative
43.6
percent and again that negative
represents a decrease so we can express
this answer in two ways we can say
negative 43.7
percent and again that negative
represents a decrease
or we can write 43.75
percent decrease
so here is one way to express our answer
and here is the other so using a
negative to represent the decrease or
writing decrease out let's move on to
number two
where we have 40 to 25
so the first thing we need to do
calculate the amount of change so the
new number
25 minus the old 40.
so we get negative 15.
divide by the old number of 40 and then
we multiply by 100
to convert it to a percent remember
always divide by the old number
so negative 15 divided by 40 is going to
give us
negative 375
thousandths multiply that by 100
so move the decimal twice to the right 1
2 and we end up with negative 37.5
percent or negative 37
and a half percent so let's express it
in
our two different ways to show our final
answer
we can say negative 37.5 percent that
negative represents a decrease
so this would be one way or we can write
it out
as 37.5
percent decrease
and there you have it there's how you
show a percent of
change and we specifically worked with
percentage
decrease i hope that helped thanks so
much for watching
until next time peace
