Highway spin off- Exit numbers

[disneychrista]

When I go to Disneyland, I know I need to take the Harbor Boulevard Exit from Interstate 5. Looking at Google maps it's exist 110A, but I never knew that.

I have no clue what exit number anything is, it is all the street name that matters. The only things that exit number helps with is to know how many more exits it is when GPS say take exit 489 toward Main Street.