Two trains leave the station at the same time on parallel tracks. One travels *560* miles in the same amount of time it takes the second one to travel *630* miles...and why do we care?

Did you spot anything special about the numbers used in this problem (that isn't a problem)? If you have good "number sense" you most likely noticed that *2, 5* and *7* are factors of both numbers. If you didn't catch that, you might want to give this instructable a try.

Students working on multi-step math problems often struggle reaching the correct answer because they have to stop and calculate a small part of the problem and by the time they have that worked out they don't remember what they needed it for. If we can train their brains to solve basic math equations without conscious effort math will get easier for them.

I developed this activity about *10* years ago in my tutoring business. I have used it successfully with students from *5* to *75*. The specialized, "Solar Powered, Recycled, Numeric Devices" needed are two decks of ordinary playing cards!

## Step 1: Getting Started

**First- Get two decks of playing cards**

Second- Remove all Kings, Queens, Jacks and Jokers (except for that one kid in the back row. He may learn something here!)

I use the cards as random number generators. I prefer two decks of cards because of the greater possible card sets. I use the aces as *1*'s. That gives me eight sets of the digits *1-10*. This number works very well for three or four students to play together.

It is not necessary to shuffle too much or to deal the cards out one at a time to the students. Students don't even need to hide their cards from each other. Some of the best teaching in this game comes from one student seeing something a neighbor can do with their cards and giving them a clue (i.e. "I see a way you can make it with four cards!")