Question 756492
Let me number be xy.

we can write it as 10x+y and after interchanging the number becomes yx which can be written as 10y+x.

(10x+y) - (10y+x) = 63

10x+y-10y-x = 63

9x-9y=63

9(x-y)=63

x-y = 7

Hence difference between digits is 7.