Whenever a number (x) is multiplied three times, then the resultant number is known as the cube of that number. Thus, the cube for the number (x) becomes x3 or x-cubed. For example, let us take the number 5. We know that 5 × 5 × 5 = 125. Hence, 125 is called the cube of 5. While on the other hand, the cube root of a number is the reverse process of the cube of a number and is denoted by ∛. Considering the same example, 5 is called the cube root of the number 125. On this page, we will learn more about the cubes and cube roots of a number.

You are watching: Simplify cube root of 7 over fifth root of 7.

1. | What is a Cube Root? |

2. | How to Find Cube Root of a Number? |

3. | What is Cube of a Number? |

4. | List of Cube Root of Numbers |

5. | FAQs on Cube Root |

## What is a Cube Root?

When we think about the words cube and root, the first picture that might come to our mind is a literal cube and the roots of a tree. Isn't it? Well, the idea is similar. Root means the primary source or origin. So, we just need to think "cube of which number should be taken to get the given number". In mathematics, the definition of cube root is written as, "**Cube root is the number that needs to be multiplied three times to get the original number."** Now, let us look at the cube root formula, where y is the cube root of x. ∛x = y. The radical sign ∛ is used as a cube root symbol for any number with a small 3 written on the top left of the sign. Another way to denote cube root is to write 1/3 as the exponent of a number.

Cube root is an inverse operation of the cube of a number.

**Perfect Cubes:**

A perfect cube is an integer that can be expressed as the product of three same or equal integers. For example, 125 is a perfect cube because 53 = 5 × 5 × 5 = 125. However, 121 is not a perfect cube because there is no number, which when multiplied three times gives the product 121. In other words, a perfect cube is a number whose cube root is an integer. The following table shows the perfect cubes of the first 10 natural numbers.

Number/Cube root | Perfect cube |

1 | 1 |

2 | 8 |

3 | 27 |

4 | 64 |

5 | 125 |

6 | 216 |

7 | 343 |

8 | 512 |

9 | 729 |

10 | 1000 |

## How to Find Cube Root of a Number?

The cube root of a number can be determined by using the prime factorization method. In order to find the cube root of a number, start with the prime factorization of the given number. Then, divide the factors obtained into groups containing three same factors. After that, remove the cube root symbol and multiply the factors to get the answer. If there is any factor left that cannot be divided equally into groups of three, that means the given number is not a perfect cube and we cannot find the cube root of that number. For example, let us see how we find the cube root of 15625.

## What is Cube of a Number?

When we multiply a number three times by itself, the resultant number (product) is known as the cube of the original number. We call it a cube because it is used to represent the volume of a cube. In other words, a number raised to exponent 3 is called the cube of that number. For example, the cube of 3 is 27. That means 3 × 3 × 3 = 27, and it can be written as 33. Similarly, the cube of 4 is 64, and the cube of 5 is 125, and so on.

To find the cube of a number, first, multiply that number by itself, then multiply the product obtained with the original number again. Let us find the cube of 7 through the same process. We know that the cube of a number N is N × N × N. So, the cube of 7 is 7 × 7 × 7. Now, in order to find the cube of 7, we will first find the value of 7 × 7. This value is 49. Now, we will find 49 × 7. This is equal to 343. Hence, we can say that cube of the number 7 is 343.

### Cube of a fraction

Similar to the cube of a number, the cube of a fraction can be found by multiplying it three times. For example, the cube of the fraction (2/5) can be written as 2/5 × 2/5 × 2/5. Simplifying it further, we get the value of cube as (2 × 2 × 2) / (5 × 5 × 5). This is equal to (23/ 53) = 8/125.

### Cube of Negative Numbers

The process to find the cube of a negative number is the same as that of a whole number and fraction. Here, always remember that the cube of a negative number is always negative, while the cube of a positive number is always positive. For example, let us try finding the cube of -7.

See more: What Is The Most Important External Issue When Using Social Media In Emergency Management?

We know that the cube of -7 is (-7) × (-7) × (-7). Now, in order to find the cube of (-7), we will first find the value of (-7) × (-7). This value is 49. Now, we will find 49 × (-7). This is equal to -343. Hence, we can say that cube of the number -7 is -343.