Basic Math/fractions

Question
Its been years since i did math, i cant even help my daughter.

how do i solve these 2 problems:
-6/7 - 12/13
1/11 + (-7/9)

You need common denominators.  The easiest way to find a common denominator is to multiply the 2 denominators together, so for the first problem, use 91 and for the second use 99.  Now, convert each fraction to the common denominator, so 6/7 = 78/91, 12/13 = 84/91, 1/11= 9/99 and 7/9 = 77/99 (if you don't know how to convert fractions, let me know).  Now that you have common denominators, you can do the addition or subtraction

-78/91 - 84/91 = -162/91, which reduces to -1 71/91

9/99 + (-77/99) (which is the same as 9/99 - 77/99) = -68/99

Basic Math

Volunteer

Lynn Houston

Expertise

I can answer questions in basic algebra and any grade school math.

Experience

Love math, currently helping my nephew get through Intermediate Algebra.

Education/Credentials
I majored in Math Ed in college (but decided not to teach), so have over 40 credits of math.