The second part of the Four Fours

The four fours is a rather famous little puzzle that requires some creativity and also gets people thinking about how the operations interact with each other. One thing I find both frustrating and fascinating is what happens when people come up with numbers that are very hard to produce with the standard basic operations of addition, subtraction, multiplication and division. People seem to be focused on producing the results in any way they can, rather than asking whether it's possible to produce the results. You also start getting solutions using All The Things, even though it's totally possible to get the answer for some of them just using the most basic of operations.

So here's the question: how do I arrange the Four Fours puzzle to make it more natural for people to consider what they can or can't achieve using just the basic operations, and if new operations are allowed, how do I prevent it from becoming All The Things?

You can read the rest of this blog post, and two related blog posts, in PDF form here.

The titles of the three posts in the series are:

• Four alternatives to the four fours
• A day of maths: Zero Zeros
• The second part of the four fours