作业帮简便计算:9.99x22.2+33.3x3.34 1/3+1/15+1/35+1/63+1/99+1/143
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/11 05:47:50
简便计算:9.99x22.2+33.3x3.34 1/3+1/15+1/35+1/63+1/99+1/143
简便计算:9.99x22.2+33.3x3.34 1/3+1/15+1/35+1/63+1/99+1/143
简便计算:9.99x22.2+33.3x3.34 1/3+1/15+1/35+1/63+1/99+1/143
9.99x22.2+33.3x3.34
=0.3x33.3x22.2+33.3x3.34
=33.3x(0.3x22.2+3.34)
=33.3x(6.66+3.34)
=33.3x10
=333
1/3+1/15+1/35+1/63+1/99+1/143
=1/3+1/(3x5)+1/(5x7)+1/(7x9)+1/(9x11)+1/(11x13)
=1/3+1/2*(1/3-1/5)+1/2*(1/5-1/7)+1/2*(1/7-1/9)+1/2*(1/9-1/11)+1/2*(1/11-1/13)
=1/3+1/6-1/26
=1/2-1/26
=13/26-1/26
=6/13
解由9.99x22.2+33.3x3.34
=99.9x2.22+33.3x3.34
=33.3×3x2.22+33.3x3.34
=33.3×6.66+33.3x3.34
=33.3（6.66+3.34 ）
=33.3×10
=333
2 1/3+1/15+1/35+1/63+1/99+1/143
=1/2(1/1-1/3)+1/2(1/3-1/5)+1/2(1/5-1/7)+1/2(1/7-1/9)+1/2(1/9-1/11)+1/2(1/11-1/13)
=1/2(1/1-1/13)
=6/13
第一题太简单，应该会做的，相信你。
第二题
1/3+1/15+1/35+1/63+1/99+1/143
=（1-2/3）+（2/3-3/5）+（3/5-4/7）+（4/7-5/9）+（5/9-6/11）+（6/11-7/13）
=1-7/13
=6/13
第一个
9.99x22.2+33.3x3.34
=0.3x33.3x22.2+33.3x3.34
=33.3x(0.3x22.2+3.34)
=33.3x(6.66+3.34)
=33.3x10
=333
第二个=1/1*3+1/3*5+1/5*7+1/7*9+1/9*11+1/11*13
=1/2*(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)=1/2*(1-1/13)
=1/2*(1-1/3)
` =6/13