Ⅰ 3道奥数题的简便算法
1、原式=1\42+1\56+1\72+1\90=(1/6-1\7)+(1\7-1\8)+(1\8-1\9)+(1\9-1\10)=1\6-1\10=1\15
3、原式=(1-1\2000)*2001=2001-1又1\2000=2000又2000\2000-1又1\2000=1999又1999\2000
Ⅱ 两道数学计算题（简便算法）
(-3.14)*35.2+6.28*（-23.3）-1.57*36.4
=(-1.57*2)*35.2+1.57*4&(-23.3)-1.57*36.4
=1.57*[35.2*(-2)+4*(-23.3)-36.4]
=1.57*[-70.4-93.2-36.4]
=1.57*(-200)
=-314
(-1)*1/2-1/2*1/3-1/3*1/4-1/4*1/5-.....-1/98*1/99-1/99*1/100
=-(1/1-1/2)-(1/2-1/3)-(1/3-1/4)-(1/4-1/5)-......-(1/98-1/99)-(1/99-1/100)
=-1/1+1/2-1/2+1/3-1/3+1/4-1/4+1/5-.....-1/98+1/99-1/99+1/100
=-1/1+1/100
=-99/100