Question

4.25÷2.5ⅹ9.9+1.7的简便计算，火急火燎的!麻烦了!

Answer 1

4.25÷2.5×9.9+1.7的简便计算如下：
4.25÷2.5×9.9+1.7
=（4.25×4）÷（2.5×4）×9.9+1.7
=17÷10×9.9+1.7
=1.7×9.9+1.7
=1.7×（9.9+1）
=1.7×（10+0.9）

=1.7×10+1.7×0.9
=17+1.7×1-1.7×0.1
=17+1.7-0.17
=18.7-0.17
=18.53

Answer 2

思路：将 2.5 化为分数形式 10/4，将 9.9 化为 (10-0.1) 形式 

演算：4.25÷2.5ⅹ9.9+1.7
=4.25÷(10/4)ⅹ(10-0.1)+1.7
=4.25ⅹ(4/10)ⅹ(10-0.1)+1.7
=4.25ⅹ4-0.425ⅹ4ⅹ0.1+1.7
=17-0.17+1.7
=18.7-0.17
=18.53

Answer 3

4.25÷2.5ⅹ9.9+1.7
=5÷2.5ⅹ9.9-0.75÷2.5ⅹ9.9+1.7
=2ⅹ9.9-0.3ⅹ9.9+1.7
=19.8-2.97+1.7
=19.8-3+0.03+1.7
=16.8+1.73
=18.53