Question

7.5✘4.2✘1.3怎么简便计算？

Answer 1

7.5✘4.2✘1.3怎么简便计算？
7.5✘4.2✘1.3
=2.5 x3 x(4+0.2)x1.3
=(2.5x3x4+2.5x3x0.2 )x1.3
= (30+1.5)x1.3
= (30 +1 +0.5)x1.3
=30x1.3 + 1x1.3 +0.5x1.3
=39+1.3+0.65
=40.95

Answer 2

解:7.5x4.2x1.3
=7.5x(4+0.2)x(1+0.3)
=(7.5x4+7.5x2)x(1+0.3)
=(30+1.5)x(1+0.3)
=4.5x(1+0.3)
=4.5+1.35
=5.85

Answer 3

7.5*4.2*1.3
=（7.5*(4+.2))*1.3
=（7.5*4+7.5*2）*1.3
=（30+15）*1.3
=45*1.3
=45*（1+0.3）
=45+45*0.3
=45+13.5
=58.5

Answer 4

7.5ⅹ4.2x1.3
=0.75ⅹ42ⅹ1.3
=3/4x42x1.3
=(21ⅹ3x1.3)/2
=21x3.9/2
=21x(4-0.1)/2
=(84－2.1)/2
=42－1.05
=40.95

Answer 5

原式为：7.5×4.2×1.3＝2.5×3×6×0.7×（1+0.3）＝2.5×3×6×0.7×1+2.5×3×6×0.7×0.3＝2.5×3×6×0.7+2.5×3×6×0.7×0.3＝5×3×3×0.7+5×3×3×0.7×(1-0.7)＝5×3×3×0.7+5×3×3×0.7-5×3×3×0.7×0.7＝10×3×3×0.7-5×3×3×0.7×0.7＝9×7-0.5×9×7×0.7＝9×7×（1-0.35）＝63×0.65＝40.95