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?
$E$ = number of erasers
$C$ = number of crayons
$e$ = number of erasers spent
$c$ = number of crayons spent

$E$ + $C$ = 1074 
$E$ - $e$ = 457 
$C$ - $c$ = 523 
$e$ + $c$ = 580

1074 = 457 + 523 
457 = 580 - 523 
523 = 580 - 457 

$C$ - $E$ = 66