How do I tackle fractional powers?

The main thing to know when answering these sorts of questions is that the denominator of the fraction is the root you take of the given number. For example, 161/2 is the same as the sqaure root of 16, which is 4. Or 1251/3 is the cube root of 125 which is 5. However, if the numerator is not 1 then there is more to consider: Take x2/3 for example: We know from laws of indices that x2/3 is the same as (x1/3)2 because when you raise one power to another power, you multiply them together. Once we have done this, the question becomes much simpler; you first take the cube root of x, and then square it. e.g. 'What is 813/4?' Consider it as (811/4)3: First take the bit in the brackets, which is equal to 3. Then cube this result which is equal to 27. So the answer is 27.

CS
Answered by Cameron S. Maths tutor

3009 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Work out the increase in price from £1.50 to £2.00 as a percentage.


How do you know which circle theorems to use when answering a question?


Vectors a and b are defined by a = 2i + 3j and b = 4i - 2j, find 3a-b in terms of i and j


What are the different methods of solving quadratic equations?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning