There were some pencils in a pencil box. zoe added 7 more pencils to the pencil box. now there are 24 pencils in the box. how many pencils were in the box to start with?

Jordan rides his bike 6 7/15 miles every day to deliver newspapers and to go to and from school. if his ride to and from school is 4 3/10 miles, how many miles is the trip to deliver newspapers? 1 1/3 1 1/6 2 1/6 2 4/5

Pls! does anybody know a shortcut for answering these types of questions in the future?

Nine more than four times a number is the same as one less than twice the number. find the number?