Question

脱式计算:一、用简便方法计算下面各题。(5/17×4/13)×17×13 = = = =

Answer 1

20

Answer 2

(5/17×4/13)×17×13
=5/17×4/13×17×13
=（5/17×17）×（4/13×13 ）
=5×4
=20