Question 126137
Give the fractions all a common denominator.  Do that by finding a common multiple for all of them.  In this case it is 8 since you can multiply each denominator by some number to get 8.  So change 1/2 to 4/8 by multiplying by 4/4.  Change 1/4 to 2/8 by multiplying by 2/2.  And leave 1/8 as it is.  So we have (4/8)+(2/8)_(1/8).  So add the numerators to get (4+2+1)/8=7/8