Question

找规律 21-12=9=9*1 32-23=9=9*1 43-34=9=9*1 31-23=18

Answer 1

51-15＝36＝9*4

62-26＝36＝9*4

61-16＝45＝9*5

72-27＝45＝9*5

71-17＝54＝9*6

以此类推...