1.2009/(2009+2009/2010)=2009*2010/(2009*2010+2009)=2009*2010/2009*2011
=2010/2011
2.1/3*(1/5-1/8+1/8-1/11...+1/98-1/101)=1/3*(1/5-1/101)1/3*96/505=32/505
两道简便计算题,急用!1.2009÷2009.2009/2010（2009除以2009又2010分之2009）2.1/5
1.2009/(2009+2009/2010)=2009*2010/(2009*2010+2009)=2009*2010/2009*2011
=2010/2011
2.1/3*(1/5-1/8+1/8-1/11...+1/98-1/101)=1/3*(1/5-1/101)1/3*96/505=32/505