hey there it's Kaeleigh in this lesson we're going to talk about converting
between the different units used to measure the volume of liquids in our
last lesson we filled out this chart for cups pints quarts and gallons and we
discovered when we're moving from cups to pints we can divide by two to find
how many pints when we're moving from pints to quarts we can also divide by
two and when we're moving from quarts to gallons we discovered we divide by four
so that's us going from smaller to larger in our units but if we're gonna
go the other way we're gonna go from gallons to quarts we would have to
multiply by four so one gallon is equal to four quarts so I have to multiply by
four to get to quarts if I have four quarts and I'm going to pints what do I
have to multiply for four quarts is equal to eight pints
so that means four quarts times two wait tell me how many pints I have and if I'm
going from pints to cups if I have eight pints and that's equal to sixteen cups I
have to multiply by two again so these numbers here are called conversion
factors and conversion factors are numbers or fractions that are used to
help us convert between units so remember when we use these pictures to help us
figure out our conversions so we could rewrite these as our conversion factors
so two cups is equal to one pint so if I have two cups and I'm converting to one
pint remember I have to divide by two but dividing by two
the same as saying 1/2 times 1/2 so this 1/2 is actually one pint over 2 cups so
this picture is saying this conversion factor and this picture
remember if I'm going from pints to quarts I divide by two and that's the
same as multiplying by 1/2 but that 1/2 is actually saying one
quart is equal to two pints and now for this one if I'm going from quarts to
gallons remember I have to divide by 4 and that's the same as multiplying by
1/4 and that 1/4 actually means 1 gallon is equal to 4 quarts so these fractions
here are my conversion factors when I want to find the top numbers units so
here do you see we have our conversion factors these fractions here and we know
what these fractions really mean it's saying one pint is equal to two cups one
quart is equal to two pipes and one gallon is equal to four quarts now
everything is zero here because we're starting with zero cups I have this here
I'm going to change the number of cups and we're gonna see how they all relate
to each other so if I change this here let's say two cups because we know this
one two cups is equal to one pint and one
pint is equal to well we have to multiply it by our conversion factor
which says one quart is equal to two pints so if I multiply 1 times 1/2 I get
half of a quart now if I have half of a quart I have to
multiply it by my conversion factor 1 gallon over 4 quarts and I get zero
point 1 3 gallons so let's increase it again let's go all the way to 16 cups so
here I have 16 cups if I multiply that by my conversion factor of pints and
cups I have to multiply by 1/2 or 1 pint over 2 cups 16 multiplied by 1/2 is the
same as dividing by 2 I get 8 pints now if I've eight pints and I want to
convert it to quarts now I can multiply it by my conversion
factor of quarts and pipes it's important to notice here that we have
pints on the bottom of our conversion factor why because I need to cross out
my units here to leave me with just chords on top and now I'm converting 4
quarts to gallons I know there's 4 quarts and every one gallon or I can use
my conversion factor and divide 4 quarts by 4 quarts and I get 1 gallon so let's
do this example together it says how many quarts are in 10 pints so we're
going we're converting pints to quarts so all right now what I know 10 pints
and I want to know 10 pints is equal to how many quarts so I need a conversion
factor that will have pints to quarts and that is this one here one quart is
equal to 2 pints now notice when I do my multiplication with my fraction here I
can cancel out my pints unit so I'm left with just quarts up here which is good
because that's what I want my answer and so now I have 10 over 2 quarts
is equal to 10 divided by 2 is 5 quarts so here I have a trickier one it says
how many gallons are in 40 cups so I'm converting from cups to gallons we write
down what we know 40 cups and I'm gonna convert it to gallons so I need to
multiply by my conversion factor but do you know a conversion factor for cups to
gallons well all we really need to know is this right here one gallon is equal
to 16 cups so our conversion factor is 16 cups over one gallon but to do this
here I want gallons as my answer I need cups on the bottom so I'm gonna have to
flip this fraction over so I'll have 16 cups on the bottom one gallon on top and
I'm gonna go ahead and do this multiplication I know I can cross out my
cups and I end up with 40 gallons over 16 so now this looks like a division
problem right I'm gonna just go ahead and use my calculator 16 goes into 42
and a half times so 40 cups is equal to 2 and 1/2 gallons
awesome job learning how to convert between these units of volume for
liquids practice what you've learned by doing the online games and quizzes have
fun and remember to always be clever