Question

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.

Answer 1

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