问题
解答题
用简便方法计算．
0.125×32×25
15.4×1.7+9.3×15.4-15.4
0.8+0.98+0.998+0.9998
4.28×34.5+3.45×57.2．
答案
（1）0.125×32×25
=0.125×8×4×25
=0.125×8×（4×25）
=1×100
=100；
（2）15.4×1.7+9.3×15.4-15.4
=（1.7+9.3-1）×15.4
=10×15.4
=154；
（3）0.8+0.98+0.998+0.9998
=1-0.2+1-0.02+1-0.002+1-0.0002
=4-0.2222
=3.7778；
（4）4.28×34.5+3.45×57.2
=42.8×3.45+3.45×57.2
=（42.8+57.2）×3.45
=100×3.45
=345．