将1/2+1/12+1/30+1/56+1/90写成分母是连续自然数的五个真分数的和．
问题描述：
将
+1 2
+1 12
+1 30
+1 56
写成分母是连续自然数的五个真分数的和． 1 90
答
原式=
+(1 2
−1 3
)+(1 4
−1 5
)+(1 6
−1 7
)+(1 8
−1 9
)，1 10
=(
−1 3
)+1 6
+(1 7
−1 2
−1 4
)+1 8
+(1 9
−1 5
)，1 10
=
+1 6
+1 7
+1 8
+1 9
．1 10