An accidental cancellation is reducing a fraction by canceling individual digits in the numerator and denominator.
In some cases the result is equal to that obtained by a correct process.
16/64 = 1
26/65 = 2
266/665 = 2
Try to find two-digit cases in bases other than base 10,(e.g. 13/32 = 1/2 ( the only solution in base 4).