Explain how you would write 35% as the sum of two benchmark percents or as a multiple of a fraction?

Ineed asap. i cant understand this question i need someone to me right away

You are a clerk at convenience store. a customer owes 11.69 for a bag of potatoes chips. she gives you a five dollar bill. how much change should the customer receive?

How do you figure out which order to do two step equations in? like which thing do you subtract/add/multiply/divide first? i understand that you do the opposite of whatever's shown on the opposite side, but when?