David Weber, Talei Kunkel, Harriet Simand and, Justin Medved Solutions for Chapter: Numbers and Number Systems Civilizations and Human Interactions, Exercise 21: GCF and LCM strategies

Sliced ham comes in packages of $10$. Cheese slices come in packages of $8$. Bread rolls come in packages of $12$. What is the least number of all three items you must buy in order to make the same number of ham and cheese sandwiches with nothing left over? 

You have a piece of construction paper that measures $32$ cm by $48$ cm. You want to cut it into squares of equal size. What will be the dimensions of the largest possible square? How many squares will you have? 

At a train station, the blue line has a train leaving every $15$ minutes, the green line has a train leaving every $24$ minutes, and the red line every $10$ minutes. If the first train on each line leaves at the same time, how often will there be trains on all three lines departing the train station at the same time? 

You have $54$ hockey cards, $72$ baseball cards, and $63$ basketball cards, and you want to put them in a binder. Each page of the binder should have cards from a single sport, and there should be the same number of cards on each page. What is the greatest number of cards you can put on a page? How many pages will you need for each sport?