Guest Posted July 26, 2008 Report Share Posted July 26, 2008 What is the last number in this math problem 7 to the 25th power Quote Link to comment Share on other sites More sharing options...
0 TwoaDay Posted July 27, 2008 Report Share Posted July 27, 2008 is it 0 that seems kind of easy Quote Link to comment Share on other sites More sharing options...
0 TwoaDay Posted July 27, 2008 Report Share Posted July 27, 2008 actually i think im wrong ill try to find the real answer now Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 (edited) 7. every 5th power of 7 is seven. pattern=7 9 3 1 7 9 3 1 7... Edited July 27, 2008 by lemonymelon Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 it is not 0 or 5 try again Quote Link to comment Share on other sites More sharing options...
0 TwoaDay Posted July 27, 2008 Report Share Posted July 27, 2008 well actally i was right with 0 my calculator doent show the whole 7 to the 25th but 7 to the 24th is 191581231380566400000 so that times 7 must end in 0 Quote Link to comment Share on other sites More sharing options...
0 TwoaDay Posted July 27, 2008 Report Share Posted July 27, 2008 whoops my bad Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 (edited) it's what i said it was i checked on calculator unless..maybe you weren't paying attention when you said the answer wasn't 0 or 5 and you meant to say it wasn't 0 or 7 because 5 is the last number in the question so it could be the real answer Edited July 27, 2008 by lemonymelon Quote Link to comment Share on other sites More sharing options...
0 TwoaDay Posted July 27, 2008 Report Share Posted July 27, 2008 (edited) what is the number? Edited July 27, 2008 by TwoaDay Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 it's what i said it was i checked on calculator no it is not 5 just because 7x5 is 35 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 i didn't say 5, did i, now? Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 i didn't say 5, did i, now? sorry but 7 is not right it is 3 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 actually i think im wrong ill try to find the real answer now it is a 3 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 why? oh and welcome to the den usually people don't give the answers out till they get more replies Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 7. every 5th power of 7 is seven. pattern=7 9 3 1 7 9 3 1 7... the 7x7=49 x7=343x7=2401x7=16807x7=117649x7=823543x7=5764801 and so fourth out 25 times so it would be 9 see i even miss counted hahahaha Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 but i stil reckon it's what i said originally i checked with my calculator: 1341068619663964900807 i'm not so sure about my reasoning with the whole 5th power business being a bit silly there but the 25th unit digit ought to be what i said, right? Quote Link to comment Share on other sites More sharing options...
0 TwoaDay Posted July 27, 2008 Report Share Posted July 27, 2008 its definately 7 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 The answer is 7. The digits of the succesion of power of seven produce a periodical succesion which is:7,9,3,1,7,9,3,1... (7,49,343,2401...). Thus, the 25th element of such sucession is 7. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 It is 1341068619663964900807. I am surprised none of you solved it yet. The question was what is the last number in this sequence. The only way it would be 7 is if it was 'digit'. Quote Link to comment Share on other sites More sharing options...
0 kingofpain Posted July 27, 2008 Report Share Posted July 27, 2008 (edited) Easy way: 7^2 = 7*7 = 49 (ends with 9); 7^4 = 49*49 = A (ends with 1); 7^8 = A*A = B (ends in 1); 7^16 = B*B = C (ends in 1); 7^24 = B*C = D (ends in 1); 7^25 = D*7 = E (ends in 7); Answer ends in 7. Edit: I feel like such a tool for ending my lines in a semi colon after a Saturday evening coding session! Edited July 27, 2008 by kingofpain Quote Link to comment Share on other sites More sharing options...
0 TwoaDay Posted July 27, 2008 Report Share Posted July 27, 2008 It is 1341068619663964900807. I am surprised none of you solved it yet. The question was what is the last number in this sequence. The only way it would be 7 is if it was 'digit'. thats interesting i wonder if thats what the OP meant well its that or 7 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 What is the last number in this math problem 7 to the 25th power The Last digit is 7 That is because the last digit is cyclic in nature. The last digits are 7^1, 7^5, 7^09, 7^13, 7^17, 7^21, 7^25 = 7 7^2, 7^6, 7^10, 7^14, 7^18, 7^22 = 9 7^3, 7^7, 7^11, 7^15, 7^19, 7^23 = 3 7^4, 7^8, 7^12, 7^16, 7^20, 7^24 = 1 Quote Link to comment Share on other sites More sharing options...
0 Nikyma Posted July 27, 2008 Report Share Posted July 27, 2008 The last number in the problem is 25 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 The last number in the problem is 25 Nikyma, I think you've got it right .. GJ Quote Link to comment Share on other sites More sharing options...
0 kingofpain Posted July 27, 2008 Report Share Posted July 27, 2008 If the answer indeed is 25, then this is appropriate: Cheers! -- Vig Quote Link to comment Share on other sites More sharing options...
0 Guest Posted July 27, 2008 Report Share Posted July 27, 2008 (edited) What is the last number in this math problem 7 to the 25th power 7 7^2 = 49 (2,6,10,14,18,22) 9 x 7 = 63 (3,7,11,15,19,23) 3 x 7 = 21 (4, 8,12,16,20,24) 1 x 7 = 7 (5,9,13,17,21,25) 7 x 7 = 49 ( ... Edited July 27, 2008 by taliesin Quote Link to comment Share on other sites More sharing options...
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What is the last number in this math problem 7 to the 25th power
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