The nth Root and Fractional Indices
Learn what an nth root is and how to simplify fractional indices, like . Let’s get started! 🚀

Video Lesson
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Flashcards
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🛎️ nᵗʰ Root
- The nᵗʰ root means a number that is multiplied by itself times.
- For example, the cube root of 27 is 3 because .
🛎️ Rules of the nᵗʰ Root
- The algebraic rule is when multiplied times.
- For example, .
🛎️ Roots as Fractional Indices
- A fractional index is another way to write a root.
- The rule is
🛎️ Example:
- The fractional index means take the cube root.
- because .
🛎️ Fractional Indices Rule
- In , the denominator tells you the root.
- The numerator tells you the power.
🛎️ Example:
- Find the 4th root of 16 to get 2.
- Then raise it to the power 3 to get 8.
Practice Questions
Test your understanding
What is ?
Correct! 🎉 +10 pointsNot quite right
The cube root of 125 is 5, because . Therefore, .
What is ?
Correct! 🎉 +10 pointsNot quite right
The cube root of 64 is 4, because .
What is ?
Correct! 🎉 +20 pointsNot quite right
The cube root of 27 is 3, because . Then, raising 3 to the power of 2 gives 9.
What is ?
Correct! 🎉 +20 pointsNot quite right
First, find , which is 2 because . Then, raise 2 to the power of 3: . So, .
What is ?
Correct! 🎉 +20 pointsNot quite right
means first taking the cube root of 125, which is 5, and then squaring the result. . So, .
What is ?
Correct! 🎉 +30 pointsNot quite right
The fourth root of 16 is 2, and raising 2 to the power of 5 gives 32. So, .
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Interactive Activity
Simplifying nth roots and fractional indices
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