The difference between a constant and a variable is that a constant does not change its value as the equation is solved. Whereas, a variable changes its value, depending on the equation. The constants are generally written in numbers like fractions, integers, decimals, or real numbers. Whereas, the variables are written in letters or symbols.

Table of Contents

## What are Constants?

A constant is an entity whose value does not change throughout the calculation. A constant can be a number, fraction, or even a decimal. It is represented by a letter, symbol, or a number. For example, consider the following problem:

3 * 4 = ?

In this problem, both 3 and 4 are constants. No matter how many times you see the number 3 or 4 in this equation, they always represent the same values: 3 and 4 respectively.

Therefore, when you multiply 3 and 4 together, the result is always 12. The number 12 is also a constant because it remains fixed and doesn’t change.

So, in this example, both 3, 4, and 12 are constants.

To get more understanding related to the identification of a constant entity, you can go read the given points.

- It is a known value.
- It’s an independent figure.
- Even if its value is not determined, it remains fixed.
- It includes fractions, decimals, integers, and all real numbers.

## What are Variables?

A variable is an alphabet that is often used in mathematical equations to represent an unknown number. It is an element that can be changed while solving the mathematical equations. Some common letters used for variables are x, y, and z. Also, there are two types of variables i.e. Dependent Variable and Independent Variable.

### Dependent Variable

The dependent variable is an element that depends its value on some other variable or number. It’s called “dependent” because it depends on another number or variable. So, if that other number or variable changes, the dependent variable changes too.

For example, consider the equation z = 3 + 7y. Here, z is the dependent variable. Its value depends on what we put into the equation, which is z = 3 + 7y. So, if we change the value of y (the independent variable), the value of z will also change accordingly.

### Independent Variable

The independent variable is an element whose value is not dependent on any other variable or number. It is called “independent” as it does not depend its value on any other variable or number. So, if that other number or variable changes, the independent variable does not change too.

## What is the Difference Between Constants and Variables?

A constant is an entity whose value does not change throughout the calculation. Whereas a variable changes its value, depending on the equation. Generally, constants are written in numbers like fractions, integers, decimals, or real numbers, and the variables are written in letters or symbols.

However, these two can seem to be confusing as both Constants and Variables are important terms in the mathematical equations and expressions. Constants are like unchanging factors in the equation and variables are like the often changing factors in the equation. To understand the difference between these two terms, you can refer to the given table.

Feature | Constant | Variable |

Value | Fixed, never changes | Can change during program execution or equation |

Purpose | Represent known, unchanging values | Represent unknown or changing values |

Dependence | Independent | Depends on other integer |

Classification | There are no further classifications of constants | There are two types of variables, dependent variable and independent variable. |

Example | Speed of light (299,792,458 m/s) | x (unknown quantity in an equation) |

## Why are Constants & Variables Important?

Both constants and variables play an important role in solving a mathematical equation or problem. Below are the important points signifying the importance of the mathematical expressions, constant and variable.

- Constants stand for values that are already known in equations, expressions, or programming lines.
- Constants contain fixed values that remain unchanged throughout a problem or program.
- Variables are not fixed values and can take on different values depending on the specific problem or equation.
- Constants and play an important role in simplifying equations, both simple and complex.

### Constants vs Variables Chart

Particulars | Constants | Variables |

Definition | A constant is an entity whose value does not change throughout the calculation. | A variable is an alphabet that is often used in mathematical equations to represent an unknown number. |

Example | Let us find out the Constant in the following equation. x+y = y + 9, In this expression, x+y = y + 9, it is clearly visible that 9 is a constant because its value remains fixed throughout the equation. | Let us find out the variables in the following expressions. 3x+2 = 10, In this expression, 3x+2=10, it is clearly visible that x is a variable because its value is not specified and can vary. |

Practice Question | Find out the constant for the following expressions. 7y+5 = 11 | Find out the constant for the following expressions. z+y = y + 3 |

## Examples of Constants and Variables in Real Life

There are various examples of constants and variables in real life. For example, there is a growing kid whose height is 119 cm. Then there is a certain type of dress which fits him well. Now, with time the height of the kid will keep changing, so the height is variable, whereas, the size of the dress will remain the same, so the dress in this case is a constant.

## FAQ’s

**What is the definition of Constants?**

A constant is an entity whose value does not change throughout the calculation.

**What is the definition of Variables?**

A variable is an alphabet that is often used in mathematical equations to represent an unknown number.

**What are the types of variables?**

There are two types of variables, independent variables and dependent variables.

This was all about the “Difference between Constants and Variables”. For more such informative blogs, check out our **Study Material Section**, you can learn more about us by visiting our **Indian exams** page.