小学六年级 数学 简便计算 请详细解答,谢谢! (12 21:16:58)

2004乘20032003-2002乘20042004
=2004*2003*10001-2002*2004*10001
=2004*(2003-2002)*10001
=2004*10001
=20042004
0.65乘6.4-6.5乘0.54+65乘0.09
=0.65(6.4-5.4+9)
=0.65*10
=6.5
9999+999+99+9+5
=10000-1+1000-1+100-1+14
=11100+11
=11111
66乘44除(11乘11)
=6乘4乘11乘11除(11乘11)
=6*4
=24

.............=123456789
=948264
=17392664845
=22334456