Question

3.9×0.9+0.39的脱式

3.9×0.9+0.39的脱式

Answer 1

3.9×0.9+0.39
= 3.9×0.9+3.9x0.1
= 3.9x(0.9+0.1)
= 3.9x1
= 3.9

Answer 2

脱式简便计算
3.9×0.9+0.39
=0.39×9+0.39
=0.39×（9+1）
=0.39×10
=3.9