Let an be the integer obtained by writing all the integers from 1 to n from left to right. For example, a3=123 and a11=1234567891011. Compute the remainder when a44 is divided by 45.
a(44) mod 45 = 9
How do you know that guest?
By direct division: (1234567891011121314151617181920212223242526272829303132333435363738394041424344) / 45 = 2743484 2022469362 5367026040 4267138273 8722806062 8734029407 4300808307 5423142763.2 0.2 x 45 = 9 - The remainder.
