Paul got a box of 457 erasers and 617 crayons for his birthday. At the end of the school year he only had 523 crayons left while not having lost a single eraser. How many more crayons than erasers did he have left?

Let's denote the number of crayons as $x$ and the number of erasers as $y$. 

We know that: 

$y=x-8$

$x-y=5$

We need to solve the system of 2 equations with 2 unknowns. 

$x+y=x-y+5$

$x+y=x-(x-8)+5$

$x+y=x-x+8+5$

$x+y=8+5$

$x+y=13$

$y=13-x$

$y=5-x$

$x-y=5$

$x-(13-x)=5$

$x-13+x=5$

$2x=5+13$

$2x=18$

$x=9$

$y=9-8$

$y=1$

The answer is: There was 1 more crayon than eraser.