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;