1/8 + 1/24 + 1/48 + 1/120
= 1/8 * (1 + 1/3 + 1/6 + 1/15)
= 1/8 * (1 + 2/6 + 1/6 + 1/15)
= 1/8 * (1 + 1/2 + 1/15)
= 1/8 * (1 + 15/30 + 2/30)
= 1/8 * (1 + 17/30)
= 1/8 * 47/30
= 47/240
求采纳为满意回答.什么意思