<p>how do you calculate the cube root of something? the "fourth" root?</p>
<p>for example, how do you solve this without a calculator:</p>
<p>20736^1/4</p>
<p>You can just do factor trees, so they easiest yet most tedious manner would be to keep dividing two out until you can't anymore which in this case is eight times and you are left with three, and then you keep dividing by three and you get four factors of three. So you have 2^8 x 3^4 which equals 2^4 x 2^4 x 3^4 and since eat set of numbers is raised to the fourth power, you can then remove it from the root so you have an answer of 2x2x3 which is 12. Sorry, hope this made sense.</p>
<p>wow i suck at math sorry. get your freinds to help you. i would recommend a tutor.</p>
<p>Why would you even need to calculate the 4th root of that without a calculator? I have never seen any type of problems like that on any PSAT, SAT, AP, math test, etc.</p>
<p>Edit: except QuizBowl, but that doesn't count.</p>
<p>Tonyt88 has the best method without a calc</p>
<p>My suggestion is use a whole number like 7 then multiply times 7 ends in a 9. Multiply again and it ends in a 3. Multiply once more and ends in a 1. You can try and use that type of method. Tony has a better one. Just one more suggestion probably a little harder. Also you know 10^4 is 10000 so the number has to be more than 10. use 12 so 2x2=4x2=8x2=6. Then multiply out and 12 works.</p>