So what is the fair price for a digit wheel? 4¢ is still too high, because that makes a 10\-digit cost the same as a 16\-digit, and the 16\-digit is always better at that price\. What about 3¢? At that price, the answer is much less clear\. On the one hand, spending 3¢ on coins gets you the ability to write down only 8 possibilities, while spending 3¢ on wheels lets you write down 10 different possibilities\. On the other hand, if you're trying to store the number 101, you need either 7 coins \(7¢\) or 3 wheels \(9¢\), in which case the coins are better\. But wheels are better for storing the number 4097 \(13 coins v 4 wheels\)\. And coins are better for storing the number 10,001 \(14 coins v 5 wheels\)\. At 3¢ per wheel, which you buy depends on which number you want to store\.
I was slightly confused for the next two paragraphs, because I had a silly thought that 10,001 uses only two kinds of digits and would therefore be cheaper to store.