简便计算，需要详细过程

6.4×125＋36×12.5

=6.4×125＋3.6×125

=(6.4＋3.6)×125

=10×125

=1250

8.5－3.95－0.05＋1.5

=(8.5+1.5)-(3.95+0.05)

=10-4

=6

（14×15×48）÷（7×3×16）

=（7×2×15×48）÷（7×48）

=2×15

=30

0.625×二分之十五＋八分之五×二分之五－0.625×2

=0.625×12.5＋0.625×2.5－0.625×2

=0.625×(12.5＋2.5－2)

=0.625×13

=8.125

33333×66666

=22222×1.5×66666
=22222×99999
=22222×(100000-1)
=2222200000-22222
=2222177778

2009×20012001－2001×20092009

=2009×2001×10001-2001×2009×10001

=2009×2001×10001-2009×2001×10001

=0

1999＋999×999

=1000+999+999×999
=1000+(999+1)×999
=1000+1000×999
=1000+999000
=1000000

二分之一＋六分之一＋十二分之一＋......＋九十分之一

=1/1x2+1/2x3+1/3x4+……+1/9x10

=1-1/2+1/2-1/3+1/3-1/4+……+1/9-1/10

=1-1/10

=9/10  （10分之9）

6.4×125＋36×12.5
=12.5*(64+36)
=12.5*100
=1250
8.5－3.95－0.05＋1.5
=(8.5+1.5)-(3.95+0.05)
=10-4
=6
（14×15×48）÷（7×3×16）
=2*5*3
=30
0.625×二分之十五＋八分之五×二分之五－0.625×2
=0.625*(7.5+2.5-2)
=0.625*8
=5
33333×66666
=11111*11111*18
=123454321*18
=2222177778
2009×20012001－2001×20092009
=2009*2001*(10001-10001)
=0
1999＋999×999
=(999+1)^2

=1000 000
二分之一＋六分之一＋十二分之一＋......＋九十分之一
=1/2+1/6+1/12+……+1/90
=1/2+1/2-1/3+1/3-1/4+……+1/9-1/10
=1-1/10
=9/10 .

0.99*0.75
＝(1－0.01)* 0.75* 100/100
=(1－0.01)* 75/100
=(75-0.75)/100
=74.25/100
=0.7425