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：運算之前先觀察，為了提取公共的因數，可將1.21×0.379變成0.121×3.79，然后可以和37.9×0.0038提取37.9后再運算，本題可以依次提取，計算出結果即可．

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．
故選C．

點評：本題考查了有理數無理數的概念及運算，將1.21×0.379變成0.121×3.79是解答本題的關鍵，技巧性較強，在解答前一定要先觀察，不要盲目下手．