Question

1+1/3-7/12+9/20-11/30+13/42-15/56+17/72

Answer 1

=1+1/3-(3+4)/(3*4)+(4+5)/(4*5)-(5+6)/(5*6)+(6+7)/42-(7+8)/(7*8)+(8+9)/(8*9)

=1+1/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8+1/8+1/9

=10/9