Question

我會脫式計算． 0.325÷2.5+3.97	2.16÷3.6÷0.5	18.4+4.3×2.8
0.8×24.5-7.5	0.89×99+0.89	2.78+0.5×68．

Answer 1

分析：運用四則混合運算的順序進行計算即可，含有兩級運算，先做乘除后做加減．

解答：解：①0.325÷2.5+3.97
=0.13+3.97
=4.1；

②2.16÷3.6÷0.5
=3.6÷0.5
=7.2；

③18.4+4.3×2.8
=18.4+12.04
=30.44；

④0.8×24.5-7.5
=19.6-7.5
=12.1；

⑤0.89×99+0.89
=0.89×（99+1）
=0.89×100
=89；

⑥2.78+0.5×68
=2.78+34
=36.78．

點評：本題考查了運算的順序，注意計算結果的小數點的位置．