6.4×0.25×12.5
=(8×4×0.2)×0.25×12.5
=0.25x4x12.5x8x0.2
=1x100x0.2
=20
扩展资料:
简算常用公式
加法:a+b=b+a(加法交换律)
a+b+c=a+(b+c) (加法结合律)
a+99=a+(100-1)(近似数)
乘法:a×b=b×a(乘法交换律)
a×b×c=a×(b×c)(乘法结合律)
(a+b)×c=a×c+b×c(乘法分配律)
(a-b)×c=a×c-b×c(乘法分配律变化式)
(a+b+d)×c=a×c+b×c+d×c(乘法分配律变化式)
a×c+c=(a+1)×c(乘法分配律变化式)
6*0.25*12.5+0.4*0.25*12.5
=(4x0.25)x(0.8x12.5)x2
=1x10x2=20
6.4x0.25x12.5
=(o.25x8)x(12.5xo.8)
=2+10
=20