Quandaries
and Queries 

Perhaps you can help me. I need the number of possible number combinations, both 3 and 4 digit, from 059 I know that 09 has 10000 combinations for 4 digits Perhaps you could explain an easier way to figure this out rather than writing all these numbers down?? 

Hi Angela, I also know that there are 100 combinations of two digits from 09, and 10 ombinations of one digit from 09. How do I know this? The one digit combinations you can list. They are
I can form the two digit combinations by adding a second digit to each of the above. From a first digit of 0 I can form
From a first digit of 1 I can form
and so on. Each of the10 one digit combinations is the first digit of 10 two digit numbers. Hence there are
I can form the three digit combinations by adding a third digit to each of the 100 combinations above. From the two digit combination 00 I can form
and so on. What you can see is that each of the 100 two digit combinations forms the first two digits of 10 three digit combinations. Hence there are
Now for 059. By one "digit" combinations I expect you mean
There are 60 of them. Using the same argument as above there are 60 60 = 3600 two "digit" combinations and 60 60 60 = 216000 three "digit" combinations. Penny 

