问题 解答题

简算.①125×32×25②5×15×25×125×64 ③1992+1994+1996+1998+2000+2002+2004+2006+2008.

答案

(1)125×32×25

=(125×8)×(4×25);

=1000×100;

=100000;

(2)5×15×25×125×64

=(5×2×15)×(25×4)×(125×8);

=150×100×1000;

=15000000;

(3)第一种算法;

1992+1994+1996+1998+2000+2002+2004+2006+2008

=(1992+2008)×9÷2;

=4000×9÷2;

=18000;

第二种算法:

1992+1994+1996+1998+2000+2002+2004+2006+2008

=(1992+2008)+(1994+2006)+(1998+2002)+2000;

=4000+4000+4000+4000+2000;

=18000;

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