5 6/7 + 3 1/2. Add whole numbers first: 5+3=8. To add fractions, find number that the denominators 7 and 2 go into: 14. Express fractions in 14ths: 7 goes into 14 2 times, so 2*6=12 and 6/7=12/14. 1/2=7/14 because 2 goes into 14 7 times. Add 12/14+7/14=19/14 (add numerators), but 19 bigger than 14 and so 14 goes into 19 1 times and 5/14 over: 1 5/14. Add the 1 to the sum of the whole numbers: 8+1=9 and attach the fraction: 9 5/14. I learnt this over 50 years ago at school in England.