Check out the machine in this picture – it’s a stationary bike with a treadmill for your dog! The biker’s pedaling makes the treadmill belt move, set at the perfect speed for any size dog. Now we can all exercise together — and the dog won’t run off to chase squirrels.

*Wee ones:* Pretend you’re the dog, and run 8 steps in place! Don’t go anywhere!

*Little kids:* How many feet do the biker and the dog have together? *Bonus:* If the dog runs 10 steps at a time, then rests, how would you count up the first 70 steps by 10s?

*Big kids:* If the biker and dog run for 15 minutes outside, but then the dog chases squirrels for another 15 minutes, how long does the dog run? *Bonus:* If the dog says “woof!” after the 5^{th} step, then the 10^{th}, then the 16^{th}, then the 23^{rd}…after what step does the dog woof next?

*The sky’s the limit:* If for each dog step the biker has to step (pedal) 3 times, at what point has the biker taken 240 more steps than the dog?

__Answers:__

*Wee ones:* Count as you run in place: 1, 2, 3, 4, 5, 6, 7, 8!

*Little kids:* 6 feet. *Bonus:* 10, 20, 30, 40, 50, 60, 70.

*Big kids:* For 30 minutes. *Bonus:* After the 31^{st} step. The dog waited another 5 steps to reach 10, then another 6 steps, then another 7…so the woof comes 8 steps after that.

*The sky’s the limit:* When the biker has taken 360 steps, and the dog has taken 120. If the biker always takes 3 times as many steps, that number is the number of dog steps, plus that dog-step number 2 more times. So the gap of 240 is 2 times the number of dog steps. (If you wanted to use algebra, where the dog’s steps are the mystery number d, you’d say h = 3d, so the different between them is 3d – d = 2d = 240.)