Cube of 721

A cube number is a value obtained by raising a number to the power of 3, or by multiplying the number by itself three times. When you cube a positive number, the result is always positive. When you cube a negative number, the result is always negative. This is because a negative number by itself three times results in a negative number.

The cube of 721 can be written as 721³, which is the exponential form. Or it can also be written in arithmetic form as 721 × 721 × 721.

In order to check whether a number is a cube number or not, we can use the following three methods: multiplication method, a factor formula (a³), or by using a calculator. These three methods will help kids to cube the numbers faster and easier without feeling confused or stuck while evaluating the answers. -

1. By Multiplication Method 
2. Using a Formula 
3. Using a Calculator

The multiplication method is a process in mathematics used to find the product of two numbers or quantities by combining them through repeated addition. It is a fundamental operation that forms the basis for more complex mathematical concepts.

Step 1: Write down the cube of the given number. 721³ = 721 × 721 × 721

Step 2: You get 374,890,961 as the answer. Hence, the cube of 721 is 374,890,961.

The formula (a + b)³ is a binomial formula for finding the cube of a number. The formula is expanded as a³ + 3a²b + 3ab² + b³.

Step 1: Split the number 721 into two parts. Let a = 700 and b = 21, so a + b = 721

Step 2: Now, apply the formula (a + b)³ = a³ + 3a²b + 3ab² + b³

Step 3: Calculate each term a³ = 700³ 3a²b = 3 × 700² × 21 3ab² = 3 × 700 × 21² b³ = 21³

Step 4: Add all the terms together

(a + b)³ = a³ + 3a²b + 3ab² + b³

(700 + 21)³ = 700³ + 3 × 700² × 21 + 3 × 700 × 21² + 21³

721³ = 343,000,000 + 30,870,000 + 9,261,000 + 9,261

721³ = 374,890,961

Step 5: Hence, the cube of 721 is 374,890,961.

To find the cube of 721 using a calculator, input the number 721 and use the cube function (if available) or multiply 721 × 721 × 721. This operation calculates the value of 721³, resulting in 374,890,961. It’s a quick way to determine the cube without manual computation.

Step 1: Ensure the calculator is functioning properly.

Step 2: Enter 7 followed by 2 and 1.

Step 3: If the calculator has a cube function, press it to calculate 721³.

Step 4: If there is no cube function on the calculator, simply multiply 721 three times manually.

Step 5: The calculator will display 374,890,961.

• The cube of any even number is always even, while the cube of any odd number is always odd.

• The product of two or more perfect cube numbers is always a perfect cube.

• A perfect cube can always be expressed as the product of three identical groups of equal prime factors.

• Binomial Formula: An algebraic expression used to expand the powers of a number, written as (a + b)ⁿ, where ‘n’ is a positive integer raised to the base. The formula is used to find the square and cube of a number.

• Cube of a Number: Multiplying a number by itself three times is called the cube of a number.

• Exponential Form: A way of expressing numbers using a base and an exponent (or power), where the exponent value indicates how many times the base is multiplied by itself. For example, 2³ represents 2 × 2 × 2, which equals 8.

• Perfect Cube: A number that can be expressed as the cube of an integer. For example, 27 is a perfect cube because it is 3³.

• Volume of a Cube: The amount of space occupied by a cube, calculated as the side length cubed, V = side³.