jasen Posted September 27, 2016 Report Share Posted September 27, 2016 0,1,2,5,8,11,69,96 are spin-able numbers. We call a number is a spin-able number if : When it is typed on a calculator, then spin the calculator 180 degree, the number is still the same number with the original number. How many spin-able numbers are there from 0 to 99999 ? This is a no-computer puzzle, only right answers with explanation will be accepted. Quote Link to comment Share on other sites More sharing options...
1 Logophobic Posted September 27, 2016 Report Share Posted September 27, 2016 Spoiler One-digit numbers: (5) 0, 1, 2, 5, 8 Two-digit numbers: (6) 11, 22, 55, 69, 88, 96 Three-digit numbers: (6 * 5 = 30) - Any qualifying two-digit number with any qualifying one-digit number inserted Four-digit numbers: (6 * 7 = 42) - Any qualifying two-digit number with any qualifying two-digit number or 00 inserted Five-digit numbers: (42 * 5 = 210) - Any qualifying four-digit number with any qualifying one-digit number inserted Total: 5 + 6 + 30 + 42 + 210 = 293 Quote Link to comment Share on other sites More sharing options...
0 BMAD Posted September 27, 2016 Report Share Posted September 27, 2016 (edited) 10 hours ago, jasen said: 0,1,2,5,8,11,69,96 are spin-able numbers. We call a number is a spin-able number if : When it is typed on a calculator, then spin the calculator 180 degree, the number is still the same number with the original number. How many spin-able numbers are there from 0 to 99999 ? This is a no-computer puzzle, only right answers with explanation will be accepted. nevermind Edited September 27, 2016 by BMAD Quote Link to comment Share on other sites More sharing options...
0 bonanova Posted October 1, 2016 Report Share Posted October 1, 2016 I think Logophobic has it. Quote Link to comment Share on other sites More sharing options...
Question
jasen
0,1,2,5,8,11,69,96 are spin-able numbers.
We call a number is a spin-able number if :
How many spin-able numbers are there from 0 to 99999 ?
This is a no-computer puzzle, only right answers with explanation will be accepted.
Link to comment
Share on other sites
3 answers to this question
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.