How do you convert 7/8 to a decimal

Aiden buys two bags of chips at $1.09 each and a 20 ounce soda for $1.20 at the gas station. he knows that the state tax is 5.5. how much change will he receive from a $5 bill?

Me i’m stuck on all these questions besides the two bottom ones

Divide reduce the answer to lowest term 3/7 divided 1 1/6