So, Christina, the easiest way to find the common denominator is to multiply each by the other denominator, like you did.

However, in your first problem, the common denominator is 8, or 2(2)(2).

-7/8 +(-1/2)

Since -7/8 is already 2(2)(2), it can stay as -7/8.

-1/2 is missing 2(2), or 4. -1(4)/2(4) = -4/8

-7/8 + (-4/8) = -11/8 (if you reduce -22/16, you get -11/8).

So, let's look at 6/3 + (-1/6). The common denominator is 6, or 2(3).

36/18 - 3/18 = 33/18 = 11/6

Or, 12/6 + (-1/6) = 11/6

Make sense?

David W.

tutor

That's a good question. Either way will get you the same answer, as long as you reduce.

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04/15/18

Christina B.

04/15/18