yanjinxin
花朵
共回答了20个问题采纳率:90% 举报
1.=2×(1+3)+4×(3+5)+6×(5+7)+8×(7+9)+10×(9+11)
=2×2×2+2×4×4+2×6×6+2×8×8+2×10×10
=2×(4+16+36+64+100)
=2×220=440
2.=3333×6666+3333×3334
=3333×(6666+3334)
=33330000
3.=0.5×2×118×59÷119
=58.50420168.【请检查题目】
4.将式子倒过来:238又238/239÷238=1又1/239=240/239
所以原式=239/240
5.=(123+2又1/20)÷41
=123÷41+41/20÷41
=3+1/20=3又1/20(或61/20)
6.=0.921173486【似乎没有简便算法,检查题目是否正确】
7.=(1/2+1/4)+(1/7+1/14+1/28)-1/3-1/5-1/15-1/30
=3/4+1/4-(10+6+2+1)/30
=11/30
1年前
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