I am the owner of a pet store. If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?
If you put one canary in each cage, you have an extra bird without a cage. However, if you put two canaries in each cage then you have two canaries in the first cage, two canaries in the second cage and an extra cage.
Three brothers share a family sport: A non-stop marathon The oldest one is fat and short And trudges slowly on The middle brother’s tall and slim And keeps a steady pace The youngest runs just like the wind, A-speeding through the race “He’s young in years, we let him run,” The other brothers say “‘Cause though he’s surely number one, He’s second, in a way.”
The numbers must be in ascending order. This can be a fun one to have people work out in person, as they test out three-number series and you can tell them whether or not they satisfy the pattern.