All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
Mental Cube Root (Posted on 2004-03-10) Difficulty: 2 of 5
If the cube root of 1331 is 11 and the cube root of 1728 is 12, what is the cube root of 1442897?

(Do this one in your head - no writing or calculators allowed!)

See The Solution Submitted by Gamer    
Rating: 2.6667 (9 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution My guess | Comment 1 of 6

Since 1442897 is just over 1,000,000, the cube root must be slightly over 100. If it was 110, its cube would be 1331000, still too small by a little.  Since we want the last digit cubed to end in 7, the last number must be 3, making the answer

 

113


  Posted by Bryan on 2004-03-10 14:51:20
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (4)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information