Question

[Vũ Ngọc Anh]

1/42+1/30 +1/20 +1/12+1/6 +1/2

Answer 1

[TFBoys_Châu Anh]

1/42 + 1/30 + 1/20 + 1/12 + 1/6 + 1/2

= 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42

= 1/1.2 + 1/2.3 + 1/3.4 + 1/4.5 + 1/5.6 + 1/6.7

= 1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6 + 1/6 - 1/7

= 1 - 1/7

= 6/7 

Chú ý : Dấu " . " là dấu x

Answer 2

[Phan The Anh]

e lam cai gi vay ban ko co cau hoi sao hieu