Q) a and b are positive integers.Which unit digit(s) of a result(s) in the maximum possible absolute difference in unit values of ab and a(b+1)?
- 1
- 2
- 3
- 6
- 7
- 9
Ans) 1,9
My doubt is, on expanding and taking difference of both the terms we get ab-ab-a=|-a|=a
So, the maximum possible value of a should be 9.Kindly explain how 1 is also the answer and where am I making mistake.Thanks .