Hello. High school student. Bad with math. I have a pre-test work sheet and I need help on some of the questions. My real test is in two days.

EX:

1/2 + 2/3

I know this equals 3/5, but it wants me to reduce to lowest terms. I looked at the answer key and the answer is 11/6. I am confused as how it got reduced there... there's also another one on subtraction. Can I get help with both?

More questions.

EX:

"There's a sale. 1/4 off of the price $39 dollar jeans. What is the total cost?" I don't know how to do this...

EX:

"Truck rental terms. Hourly rate is $12, plus $0.13 per mile. Jack rented a truck at 9:30 AM and returned it ar 1:00 PM. He drove 16 miles. How much was he charged for time and mileage?" How do I write this into an equation to figure it out...??

Lastly, can someone direct me to a video that simply breaks down inches, feet, centimeters, and millimeters and all that. We come across measurement a lot and I get lost quickly... that'd be helpful.

Thank you reading and I'd appreciate some help.