`M = 1/{1 × 2} + 1/{2 × 7} + 1/{7 × 5} + 1/{5 × 13} + ... + 1/{50 × 97}`
`1/2 × M = 1/{4 × 7} + 1/{7 × 10} + 1/{10 × 13} + .... + 1/{97 × 100}`
`1/2 × 3 × M = 3/{4 × 7} + 3/{7 × 10} + 3/{10 × 13} + ... + 3/{97 × 100}`
`3/2 × M = 1/1 - 1/4 + 1/4 - 1/7 + 1/7 - 1/10 + 1/10 - 1/13 + ... + 1/97 - 1/100`
`3/2 × M = 1/1 + 1/4 - 1/4 + 1/7 - 1/7 + 1/10 - 1/10 + 1/13 - 1/13 + ... + 1/97 - 1/97 - 1/100`
`3/2 × M = 1/1 + 0 + 0 + 0 + 0 + ... + 0 - 1/100`
`3/2 × M = 1/1 - 1/100`
`3/2 × M = 99/100`
`=> M = 99/100 : 3/2`
`M = 198/300 = 33/50`
`#dtkc`
