7/15x3/8+1/15x7/16+1/15x3又1/2要脱式计算
已知1-1/3=2/1x3,计算1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=
-13x3/2+3/1x(-13)-0.34x7/2-7/5x0.34用简便方法计算
计算:1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8+1/8x9+1/9x10.
2/1x3+2/3X5+2/5x7=2/7x9+2/9x11
1+2X3+4X5+6X7+8X9=303
先阅读再计算2/1x3=1-1/32/3x5=1/3-1/52/5x7=1/5-7=1/7试计算1/1x3+1/3x5+
计算:1/1x3+1/3x5+1/5x7+1/7x9+……+1/2011x2013
计算:1/1x3+1/3x5+1/5x7+...1/2009x2011+1/2011×2013
1/1x3+1/3x5+1/5x7+.+1/1997x1999 简便计算.
计算1/1X3+1/3x5十1/5X7+.+1/2009x2011
26分之5除以7除以39分之10 5分之1X7除以15分之14 2分之3除以4分之5X3分之5 8分之5除以12分之5除
计算①1x2/1+2x3/1+3x4/1+```+19x20/1= ②1x4/1+4x7/1+7x10/1+```+91