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Perhaps you can help me. I need the number of possible number combinations, both 3 and 4 digit, from 0-59

I know that 0-9 has 10000 combinations for 4 digits I also know that 0-9 has 1000 combinations for 3 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 0-9, and 10 ombinations of one digit from 0-9. How do I know this?

The one digit combinations you can list. They are

0 1 2 3 4 5 6 7 8 9

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

00 01 02 03 04 05 06 07 08 09

From a first digit of 1 I can form

10 11 12 13 14 15 16 17 18 19

and so on. Each of the10 one digit combinations is the first digit of 10 two digit numbers. Hence there are

10 10 = 100 two digit combinations.

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

000 001 002 003 004 005 006 007 008 009

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

10 10 10 = 1000 three digit combinations.

Now for 0-59. By one "digit" combinations I expect you mean

0 1 2 3 4 ... 56 57 58 59

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

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