7道简便计算、一道10分.( / ←此为分数线)1.1×2+2×3+3×4+……10×112.9999×2222+3333×33343.0.5×236×59/1194.238÷238又238/239 (带分数)5.125又1/20(带分数)÷416.6209/10013×10693/22869÷3337/106027.(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)

问题描述:

7道简便计算、一道10分.( / ←此为分数线)
1.1×2+2×3+3×4+……10×11
2.9999×2222+3333×3334
3.0.5×236×59/119
4.238÷238又238/239 (带分数)
5.125又1/20(带分数)÷41
6.6209/10013×10693/22869÷3337/10602
7.(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)

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=4402.=3333×6666+3333×3334=3333×(6666+3334)=333300003.=0.5×2×118×59÷119=58....