Selecting numbers with all odd digits
- To: mathgroup at smc.vnet.net
- Subject: [mg22170] Selecting numbers with all odd digits
- From: "Tom De Vries" <tdevries at shop.westworld.ca>
- Date: Thu, 17 Feb 2000 01:23:59 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Hello all, In one of the math classes I am teaching we are doing some work with permutations and combinations. One question in the text was, "how many positive integers less than 700 have all odd digits?" I had done the question "by hand" and then wondered how to use Mathematica to demonstrate that the solution was the correct one. I am still very far down on the learning curve in most things, but I managed to bludgeon my way to an answer (thankfully the same as mine!) Select[ Range[699], Union[ OddQ [ IntegerDigits[#]]] == {True} & ] I am sure my trial and error method can be improved upon. I am not talking speed as much as simply using Mathematica in a way that makes sense and would be more logical?? Thanks for any suggestions might have! Tom De Vries Edmonton, Alberta Canada
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- From: Daniel Lichtblau <danl@wolfram.com>
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