Multiplying Mixed Numbers: A Step-By-Step Review | How to Multiply Mixed Numbers | Math with Mr. J

[Music] welcome to math with mr j [Music] in this video i'm going to cover how to multiply mixed numbers now i'll go through one example which should be helpful for anyone looking for a quick review or refresher whether you learned this recently or years ago if you need more help or examples i dropped links to other videos on this topic down in the description let's jump into our example where we have four and a half times two and three-fifths now the first thing that we want to do is to convert our mixed numbers to improper fractions that way we have a numerator and a denominator and we can multiply straight across so in order to do this we start at the bottom so let's start at the bottom here and we work our way to the top we multiply then add so we do 2 times 4 our denominator times the whole number so 2 times 4 is 8 plus our numerator of 1. that gives us 9. so again 2 times 4 is 8 plus 1 gives us 9. that's the numerator of our improper fraction we keep our denominator of 2 the same now that improper fraction is equivalent to our mixed number they're just in different forms we're not changing the value of the problem at all when we convert to an improper fraction let's bring our multiplication sign down and then convert our other mixed number so we multiply then add so 5 times 2 is 10 plus 3 gives us 13 that's our numerator and then keep our denominator of 5 the same once we have our mixed numbers converted to improper fractions we can multiply straight across so numerator times numerator and denominator times denominator let's start with the numerators so 9 times 13 that gives us 117 and then 2 times 5 gives us 10. so that's our answer as an improper fraction 117 tenths now let's convert that to a mixed number we do that by dividing our numerator 117 by 10. now we can either do this using mental math or writing out the division problem to the side i'll do both here so 117 divided by 10 how many whole groups of 10 can we pull out of 117 well 11 that gets us to 110 we don't hit 117 exactly so we have something left over a remainder so the difference between 110 and 117 is 7 that's what's left over that's our numerator and then keep our denominator of 10 the same now if you're unable to do that using mental math you can always come to the side and write out the division problem so for example we'll start with how many whole groups of ten out of eleven one one times ten is ten subtract we get one bring down the seven so how many whole groups of 10 out of 17 1 1 times 10 is 10 subtract and we get a remainder of 7. so we get the same thing either way sometimes problems are a little more friendly and we can do them using mental math sometimes we may need to write out the division problem either way works so just to recap how we converted from an improper fraction to that mixed number we did 117 the numerator divided by 10 the denominator so how many whole groups of 10 out of 117 11. then we have a remainder of 7 which is our numerator and we keep our denominator of 10 the same always check to see if you can simplify the fractional part of a mixed number well 7 10 is in simplest form the only common factor between 7 and 10 is 1. so this is in simplest form and we are done 11 and 7 tenths so there you have it there's how you multiply mixed numbers i hope that helped thanks so much for watching until next time peace