1/1×4+1/4+7+1/7×10+······+1/28×31的简便方法是1/1×4+1/4×7+1/7×10+······+1/28×31的简便方法

1/1×4+1/4×7+1/7×10+1/10×13+···+1/2008×2011 = 1/1*4+1/4*7+1/7*10+···+1/91*94等于几? 计算5/1*4-11/4*7+17/7*10-···+41/19*22 计算1/（1*4）+1/（4*7）+1/（7*10)+------+1/(97*100)································································································ 1/1×4+1/4+7+1/7×10+······+1/28×31的简便方法是1/1×4+1/4×7+1/7×10+······+1/28×31的简便方法 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? 1/1*4+1/4*7+1/7*10+···+1/91*94等于几?（不要答案,各种求.) （1×4）分之一 +（4×7）分之一 + （7×10）分之一 ····+（97×100）分之一 1/1*4+1/4*7+1/7*10+1/10*13+~+1/97*100 1/1*4+1/4*7+1/7*10+1/10*13+…+1/298*301 1/4*1+1/4*7+1/7*10+1/10*13+1/13*16=? 1/1*4+1/4*7+1/7*10+1/10*13+1/13*16 1/4+1/4*1/7+1/7*1/10+...1/25*1/28=? 1/1*4+1/4*7+1/7*10+.+1/2005*2008 1/1*4+1/4*7+1/7*10+.+1/2005*2008 1/1*4+1/4*7+1/7*10+.+1/52*55*+1/55*58=? 1/1×4+1/4×7+1/7×10+.+1/52×55+1/55×58 1如何计算1*1/4+4*1/7+7*1/10+...+2002*1/2005 计算1/1*4+1/4*7+1/7*10+...+1/2005*2008+1/2008*2011