Question

计算下面各题，你认为怎样简便就怎么算。 2.02X8.5 1.2

计算下面各题，你认为怎样简便就怎么算。

2.02X8.5 1.25+4.6+0.75

1.6X7.5x1.25 56X1.25

3.4x7X1.5 0.8X0.25X0.4X12.5

Answer 1

2.02X8.5
=2×8.5+0.02×8.5
=17+0.17
=17.17

1.25+4.6+0.75
=（1.25+0.75）+4.6
=2+4.6
=6.6

1.6X7.5x1.25
=（0.2×7.5）×（8×1.25）
=1.5×10
=15

56X1.25
=7×（8×1.25）
=7×10
=70

3.4x7X1.5
=（3.4×1.5）×7
=5.1×7
=35.7

0.8X0.25X0.4X12.5
=（0.25×0.4）×（0.8×12.5）
=0.1×10
=1