`A = (1 - 1/10) + (1 - 1/40) + (1 - 1/88) + (1 - 1/154)`
`A = 10/10 - 1/10 + 1 - 1/40 + 1 - 1/88 + 1 - 1/154`
`A = 9/10 + 1 - 1/40 + 1 - 1/88 + 1 - 1/154`
`A = 9/10 + 10/10 - 1/40 + 1 - 1/88 + 1 - 1/154`
`A = 19/10 - 1/40 + 1 - 1/88 + 1 - 1/154`
`A = 76/40 - 1/40 + 1 - 1/88 + 1 - 1/154`
`A = 75/40 + 1 - 1/88 + 1 - 1/154`
`A = 15/8 + 1 - 1/88 + 1 - 1/154`
`A = 15/8 + 8/8 - 1/88 + 1 - 1/154`
`A = 23/8 - 1/88 + 1 - 1/154`
`A = 253/88 - 1/88 + 1 - 1/154`
`A = 252/88 + 1 - 1/154`
`A = 63/22 + 1 - 1/154`
`A = 63/22 + 22/22 - 1/154`
`A = 85/22 - 1/154`
`A = 595/154 - 1/154`
`A = 594/154`
`A = 27/7`
Mình giải theo cách lớp 5 đó, cho mình xin hay nhất nha bạn!!!!!!
@Drew Mclntyre
