what is 7 over 4 plus 7 over 8 equals? and how do i work it out?

7/4 + 7/8 - first get the same common denominator, eighths.
14/8 + 7/8 - then add them together,
= 21/8 - then get the whole numbers sorted out.
= 2 and 5/8ths
Ta-da.
Then go do something more interesting.

Edit: Yasser's been drinking it seems. That's perhaps more interesting.

7/4 + 7/8
= (2/2)(7/4) + 7/8
= 14/8 + 7/8
= 21/8
= 2 5/8

14/8 + 7/8 = 21/8 = 2 ⅝

7/4 + 7/8
= 14/8 + 7/8
= 21/8

7/4 + 7/8 = 14/8 + 7/8 = 21/8

Answer: 21/8

7/4 + 7/8
first you have to extend the fraction 7/4
you do it like this:
4 has to be 8, (cause the other fraction is 7/8)
4x2=8
now you have to extend the number 7, you'll do it by extanding it with the same number that you extamend 4 (that's 2)
7x2=14
you got number 14/8

14/8 + 7/8 = 14 +7/8
14/8 + 7/8 = 21/8

As per your question:

7/4 + 7/8

Taking the LCM of 4 and 8 comes to 8.

14/8 + 7/8

= 21/8.

Hope this helps.

If its (7/4)+(7/8) , then it = (14/8)+(7/8) = 21/8.

7/4+7/8=14/8+7/8=(14+7)/8=21/8

7/4+7/8=14/8+7/8=22/8=11/4=2 3/4