00:01
So we are trying to add negative 7 8ths plus negative 3 5ths plus 9 10ths.
00:07
So anytime you are trying to add multiple fractions together like this, you need to find a common denominator for all three fractions.
00:15
So in this case, our least common denominator is going to be 40 because it is the smallest multiple of 8, of 5, and of 10.
00:25
So i'm going to rewrite each fraction with the common denominator of 40.
00:28
So if we are looking at negative 7 8ths, we have to multiply it by 5 over 5, which again we can do because anytime you have the same number as the numerator as it is the denominator, that's like multiplying it by 1.
00:45
So you are not changing anything.
00:47
You are just rewriting the denominator so it is equal for all fractions.
00:51
So when we multiply that, we get negative 35 over 40 because 7 times 5 is 35 and 8 times 5 is 40.
01:02
So i'm going to do the same for the other two fractions.
01:05
We've got negative 3 5ths and we are going to multiply that by 8 over 8 again to get 40 on the bottom.
01:17
And 3 times 8, that's going to be 24.
01:21
And since we are multiplying a negative times a positive, it's still going to be negative...