`A = 1/100 + 2/100 + 3/100 + ... + 99/100`
`A = (1 + 2 + 3 + ... + 99)/100`
Gọi:
`B = 1 + 2 + 3 + ... + 99`
`B = (99 + 1) × [(99 - 1) : 1 + 1] : 2`
`B = 100 × 99 : 2`
`B = 4950`
Nên:
`A = 1/100 + 2/100 + 3/100 + ... + 99/100`
`A = (1 + 2 + 3 + ... + 99)/100`
`A = 4950/100`
`A = 99/2`