Cube of 128

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 multiplied by itself three times results in a negative number.

The cube of 128 can be written as 128³, which is the exponential form.

Or it can also be written in arithmetic form as, 128 × 128 × 128.

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 students to cube numbers faster and easier without feeling confused or stuck while evaluating the answers.

• By Multiplication Method
   
• Using a Formula
   
• Using a Calculator

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

Step 1: Write down the cube of the given number. 128³ = 128 × 128 × 128

Step 2: You get 2,097,152 as the answer. Hence, the cube of 128 is 2,097,152.

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

Step 1: Split the number 128 into two parts. Let a = 120 and b = 8, so a + b = 128.

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

Step 3: Calculate each term. a³ = 120³ 3a²b = 3 × 120² × 8 3ab² = 3 × 120 × 8² b³ = 8³

Step 4: Add all the terms together: (a + b)³ = a³ + 3a²b + 3ab² + b³ (120 + 8)³ = 120³ + 3 × 120² × 8 + 3 × 120 × 8² + 8³ 128³ = 1,728,000 + 345,600 + 23,040 + 512 128³ = 2,097,152

Step 5: Hence, the cube of 128 is 2,097,152.

To find the cube of 128 using a calculator, input the number 128 and use the cube function (if available) or multiply 128 × 128 × 128. This operation calculates the value of 128³, resulting in 2,097,152. It’s a quick way to determine the cube without manual computation.

Step 1: Ensure the calculator is functioning properly.

Step 2: Press 1 followed by 2 and 8.

Step 3: If the calculator has a cube function, press it to calculate 128³.

Step 4: If there is no cube function on the calculator, simply multiply 128 three times manually.

Step 5: The calculator will display 2,097,152.

• 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: It is 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: It is 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 equals 8.
   
• Perfect Cube: A number that can be expressed as the product of three identical integers.
   
• Cube Root: The number which produces a given number when cubed. For example, the cube root of 8 is 2 because 2³ = 8.