add the following

- 4/7 + [ -7/20]

7*20= 140
so -60/140 + - 49/140= 11/140?

I have no idea what you did.

-4/7 -7/20

common denominator: 140

(-80-49)/140=-129/140

thank you

I see my error

I multiplied 4 *20 and instead of writing 80 I wrote 60, which threw off the rest of the equation. Thanks

To add the fractions 4/7 and -7/20, you need to find a common denominator between the two fractions. In this case, the least common multiple (LCM) of 7 and 20 is 140.

First, determine the equivalent fractions with a denominator of 140:
For the fraction 4/7, you need to multiply both the numerator and denominator by 20 to get 80/140.
For the fraction -7/20, you need to multiply both the numerator and denominator by 7 to get -49/140.

Now that both fractions have a common denominator of 140, you can add them together by adding their numerators:
80/140 + (-49/140) = (80 - 49)/140 = 31/140.

Therefore, the sum of 4/7 and -7/20 is 31/140.