`A=1/3 - 3/4 - (-3)/5 + 1/72 - 2/9 - 1/36 +1/15`
`A = (1/3 + 3/5 + 1/15) - (3/4 + 2/9 + 1/36) + 1/72`
`A = 1 - 1 + 1/72`
`A = 1/72`.
`B=1/5 - 3/7 + 5/9 - 2/11 + 7/13 - 9/16 - 7/13 + 2/11 - 5/9 +3/7 - 1/5`
`A = (1/5 - 1/5) + (-3/7 + 3/7) + (5/9 - 5/9) + (-2/11 + 2/11) + (7/13 - 7/13) - 9/16`
`A = 0 + 0 + 0 + 0 + 0 - 9/16`
`A = -9/16`.