1、4/5×1/2+2/5÷0.6-1/152、 1/1×3+1/3×5+1/5×7+.+1/17×19+1/19×213、 9999×2222+3333×33344、【(8 又5/8-4.625)÷(2.4+1又3/5)】×50%

问题描述:

1、4/5×1/2+2/5÷0.6-1/15
2、 1/1×3+1/3×5+1/5×7+.+1/17×19+1/19×21
3、 9999×2222+3333×3334
4、【(8 又5/8-4.625)÷(2.4+1又3/5)】×50%

1、
=2/5+2/5÷3/5-1/15
=2/5+2/5×5/3-1/15
=2/5+2/3-1/15
=6/15+10/15-1/15
=15/15
=1
2、

1,
1
2,
1/1*3=1/2(1-1/3)
1/3*5=1/2(1/3-1/5)
1/19*21=1/2(1/19-1/21)
原式=1/2(1-1/3+1/3-1/5+。。。-1/19+1/19-1/21)=1/2(1-1/21)=
10/21
3,
9999*2222+3333*3334
=3333×3×2222+3333×3334
=3333×6666+3333×3334
=3333×(6666+3334)
=3333×10000
=33330000
4,
0.5
希望我的回答对你有所帮助并能采纳我为最佳答案。
谢谢您!

4/5×1/2+2/5÷0.6-1/15=2/5+10/15-1/15=6/15+10/15-1/15=11/1×3+1/3×5+1/5×7+.+1/17×19+1/19×21=1/2×(1-1/3+1/3-1/5+1/5-1/7.+1/19-1/21)=1/2×(1-1/20)=10/219999*2222+3333*3334=3333×3×2222+3...