`a) M = 1 + 3 + 5 + ... + 101`
`M = (101 + 1) . ((101 - 1) : 2 + 1)/2`
`M = 102 . ((100 : 2)+1)/2`
`M = 102 . (50+1)/2`
`M = 102. 51/2`
`M = 5202/2`
`M = 2601`
`b) S = 1 + 2 + 2^2 + ... + 2^2018 + 2^2019`
`2S = 2 + 2^2 + 2^3 + ... + 2^2019 + 2^2020`
`2S - S = (2 + 2^2 + 2^3 + ... + 2^2019 + 2^2020) - (1 + 2 + 2^2 + ... + 2^2018 + 2^2019)`
`S = 2^2020 - 1`
