Question

1/12+1/20+1/30+1/36+1/42

要正确，要写分数，大家帮帮我，我是小学生
新兰，如果大多数人和你回答一样，我将采纳你的答案

Answer 1

1/12=1/(3*4)=(1/3)-(1/4) *表示乘,同理：
1/20=1/(4*5)=(1/4)-(1/5)
1/30=1/(5*6)=(1/5)-(1/6)
1/42=1/(3*4)=(1/6)-(1/7)

四个式子相加后中间的全部抵消了，剩下1/3-1/7=4/21
再加上1/30=55/252;

Answer 2

1/12+1/20+1/30+1/36+1/42
=1/3*4+1/4*5+1/5*6+1/6*7+1/36
=1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/36
=1/3-1/7+1/36
=4/21+1/36
=55/252

Answer 3

=1/20+1/30+1/12+1/36+1/42
=1/12+1/12+1/36+1/42
=1/6+1/36+1/42
=7/36+1/42
=49/252+6/252
=55/252

Answer 4

55/252

Answer 5

55/252