Welcome to Percent of Change with Mr. J! Need help with percent increase and decrease? 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 (percentage increase and decrease). Mr. J will go through percent of change examples and explain the steps of how to calculate percent of change.
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Hopefully this video is what you're looking for when it comes to calculating percent of change.
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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 we have two examples that we're
going to go through together
in order to get this down now when we
calculate percent of change
we take the amount of change so the new
number
minus the old number and divide by the
old number
we then multiply that by 100 to convert
that
to a percent so let's jump into number
one
where we have 50 to 34 so we start with
a 50
and now we have a 34. so we had a
decrease there so keep that in mind
as we go through our problem so the
first thing we need to do
is calculate the amount of change so the
new number
minus the old number will give us that
so the new number
is 34 minus the old number of 50.
so 34 minus 50 gives us
a negative 16. now that negative
is important because it shows us that we
have a decrease
divide that by the old or original
number of 50
and then multiply by 100 to convert that
to a percent it's very important 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 so
negative 16
divided by 50 is going to give us a
negative 32 hundredths
and then multiply that by 100 again to
convert that decimal
to a percent so we can multiply that
decimal by 100
by moving the decimal twice to the right
so
1 2 and we end up with a
negative 32 percent
so we can express that answer in two
ways
just like what we wrote negative 32
percent
and that negative shows us that we had a
decrease so this would be one way
or we can write 32 percent
and then the word decrease
to show that we had a decrease so 32
percent decrease
or negative 32 now both of those
represent that percent of
change between the 50 and 34. they
represent that decrease
now remember whenever you see a negative
that represents
a decrease let's move on to number two
where we have 10 to 22
so we can see that we have an increase
there we started with a 10
and now we have a 22. so let's plug our
numbers in
and see exactly what the percent of
change is so the new number
is 22 subtract the old to get the amount
of change
so we're going to get 22 minus 10 is 12.
divide by the old or original number of
10
and then multiply by 100 to convert that
to a percent
12 divided by 10 is going to give us one
and two-tenths and then we multiply by
100
to convert it to a percent so let's move
the decimal twice to the right 1
2 and we can fill that gap with a 0
there so we end up with
120 and that
is positive so we know it's an increase
so we had a 120 percent
increase now remember we can always tell
if we have an increase or decrease
based on positive and negative a
positive
represents an increase a negative
represents a decrease and we can always
double check with the problem
so for example number one we started
with a 50
and now we have a 34. so we decreased in
value
so that's going to be a percentage
decrease
number two we started with a 10 and now
we have 22
so we increased in value and that's
going to be
a percentage increase so i hope that
helped
thanks so much for watching until next
time
peace
