Question

求一道数学题(过程）简便方法

3.6x31.4+43.9x6.4
20.05x39+200.5x4.1+40x10.05

Answer 1

3.6x31.4+43.9x6.4
=3.6x31.4+31.4x6.4+12.5x6.4
=31.4x(3.6+6.4)+12.5x8x0.8
=314+100x0.8
=314+80
=394

20.05x39+200.5x4.1+40x10.05
= 20.05x39+20.05x41+40x20.05-40x10
=20.05x(39+41+40)-400
=20.05x120-400
=2005+20.05x20-20x20
=2005+0.05x20
=2006

Answer 2

3.6×31.4+43.9×6.4=3.6×31.4+(31.4+12.5)×6.4
=3.6×31.4+31.4×6.4+12.5×6.4
=31.4×(3.6+6.4)+0.125×640
=31.4×10+0.125×8×80
=314+80=394

20.05×39+200.5×4.1+40×10.05=20.05×39+20.05×41+40×10.05
=(20+0.05)×80+(10+0.05)×40
=20×80+10×40+120×0.05
=2000+6=2006

Answer 3

1、3.6*31.4+43.9*6.4
=3.6*31.4+(31.4+12.5)*6.4
=31.4*(3.6+6.4)+12.5*6.4
=31.4*10+12.5*8*0.8
=314+100*0.8
=314+80=394
2、20.05*39+200.5*4.1+40*10.05
=20.05*39+20.05*41+40*(20.05-10)
=20.05*(39+41+40)-40*10
=20.05*120-400
=2406-400
=2006

Answer 4

3.6x31+43.9x6.4 = 31.4x(3.6+6.4)+12.5x6.4

20.02x39 + 200.5x4.1+40x10.05 = 200.5(3.9+4.1) +4x100.5=4x(100.5+2x200.5)

Answer 5

3.6x31.4+43.9x6.4
=3.6x31.4+(31.4+12.5)x6.4
=(3.6+6.4)x31.4+12.5x6.4
=314+80
=394

20.05x39+200.5x4.1+40x10.05
=20.05x（39+41）+2x20x10.05
=1604+402
=2006

Answer 6

牛，估计学过奥数