9.9×2.3 12.5×0.8×4×0.5 2.5×0.32×1.25 5.3×10.1 简便计算,要有列式.

12.5乘4.86乘0.4 ＝12.5*2.43*0.8 ＝（12.5*0.8）*2.43 ＝10*2.43 ＝24.3 12.5×4.86×0.4=12.5×0.4×2×2.43=10×2...

9.9×2.3
=（10－0.1）×2.3
=10×2.3－2.3×0.1
=23－0.23
=22.77
12.5×0.8×4×0.5
=（12.5×0.8）×（4×0.5）
=10×2
=20
2.5×0.32×1.25………变一变,就简便.
=（2.5×0.4）×（0.8×1.25）
=1×1
=1
5.3×10.1………变一变,就简便
=5.3×（10＋0.1）
=5.3×10＋5.3×0.1
=53＋0.53
=53.53