Question

37.9×0.0038+1.21×0.379+6.21×0.159=（　　）

A、0.379

B、0.121

C、1.59

D、2.02

Answer 1

分析：运算之前先观察，为了提取公共的因数，可将1.21×0.379变成0.121×3.79，然后可以和37.9×0.0038提取37.9后再运算，本题可以依次提取，计算出结果即可．

解答：解：37.9×0.0038+1.21×0.379+6.21×0.159
=3.79×0.038+0.121×3.79+6.21×0.159
=3.79×（0.038+0.121）+6.21×0.159
=3.79×0.159+6.21×0.159
=（3.79+6.21）×0.159
=10×0.159
=1.59．
故选C．

点评：本题考查了有理数无理数的概念及运算，将1.21×0.379变成0.121×3.79是解答本题的关键，技巧性较强，在解答前一定要先观察，不要盲目下手．