What is an Equation?


Equations are mathematical statements containing two algebraic expressions on both sides of an ‘equal to (=)’ sign. It shows the relationship of equality between the expression written on the left side with the expression written on the right side. In every equation in math, we have, L.H.S = R.H.S (left hand side = right hand side). Equations can be solved to find the value of an unknown variable representing an unknown quantity. If there is no ‘equal to’ symbol in the statement, it means it is not an equation. It will be considered as an expression. 1

There are different types of equations.

  • Linear equations
  • Quadratic equations
  • Cubic equations
  • Quartic equations
  • Differential equations
  • Parametric equations


Everyone uses equations.


Parts of an Equation

There are different parts of an equation which include coefficients, variables, operators, constants, terms, expressions, and an equal to sign. When we write an equation, it is mandatory to have an “=” sign, and terms on both sides. Both sides should be equal to each other. An equation doesn’t need to have multiple terms on either of the sides, having variables, and operators. An equation can be formed without these as well, for example, 5 + 10 = 15. This is an arithmetic equation with no variables. As opposed to this, an equation with variables is an algebraic equation. Look at the image below to understand the parts of an equation. 1

equation in math
Parts of an Equation

Difference Between Expression and Equation

In mathematics, you might have encountered the terms expression and equation very often. As both combines number and/or variables, people often misunderstood an expression for an equation. However, these two mathematical terms are not same, and a big difference lies in their arrangement, that explains what they represent. The best way, to identify, whether a given problem is an expression or equation is that if it contains an equal to sign (=) it is an equation.

However, if it does not contain an equal to (=) sign, then it is just an expression. It carries numbers, variables and operators, that are used to show the value of something. Go through this article to understand the basic differences between expression and equation. 2

Comparison Chart – Key Differences

Definition of Expression

In mathematics, the expression is defined as a phrase that groups together numbers (constant), letters (variables) or their combination joined by operators (+, -, *, /), to represent the value of something. An expression can be arithmetic, algebraic, polynomial and analytical.

As it does not contain any equal to (=) sign, so, it does not show any relationship. Hence, it has nothing like left side or right side. An expression can be simplified by combining the like terms, or it can be evaluated, inserting values in place of the variables to arrive at a numerical value. 2

Definition of Equation

In mathematics, the term equation means a statement of equality. It is a sentence in which two expressions are placed equal to one another. In order to satisfy an equation, it is important to determine the value of the variable concerned; this is known as solution or root of the equation.

An equation can be conditional or an identity. If the equation is conditional, then the equality of two expressions is true for a definite value of variable involved. However, if the equation is an identity, then the equality is true for all the values held by the variable. 2


Why do we have to learn math equations? Why equations are important in our life? So many other questions arise in students mind. If you think equations are pure math or physics, then you are wrong. Equations are actually used by us in daily life. As we know most of the mathematics is depends on equation and mathematics is one of the disciplines which we utilize in everyday life. Thus, we use equations very frequently in daily life.

Today’s computer chips used in all the machines we use in daily routine like washers, dryers, cars, backs, etc. All chips, which we use in these machines based on mathematical equations and algorithms.

We use the internet to look up the information. We just type the words and get many websites related to that word. Do you ever think the process behind this internet search? This is all the parts of mathematics equations, which allow us to get information from all over the world within seconds.

Mathematical equations are also used in traffic control, aircraft, space program and medicine and so on. So we should always remember that any math equation result has the potential to change the world. That is the reason all mathematical equations are important in our life. 3

See Theoretical Knowledge Vs Practical Application.


Many of the References and Additional Reading websites and Videos will assist you with understating and applying equations.

As some professors say: “It is intuitively obvious to even the most casual observer.


1 “Equation – Definition, Types, Examples | Equation In Maths”. 2022. CUEMATH. https://www.cuemath.com/algebra/equation/.

2 Surbhi, S. 2016. “Difference Between Expression And Equation (With Comparison Chart) – Key Differences”. Key Differences. https://keydifferences.com/difference-between-expression-and-equation.html.

3 Marsh, John. “Why Equations Are Important In Our Life”. 2018. Medium. https://medium.com/@john_marsh7/why-equations-are-important-in-our-life-6eeddf8ec015.

Additional Reading

“10 Everyday Reasons Why Equations Are Important In Your Life”. 2022. mathworksheetscenter.com. https://www.mathworksheetscenter.com/mathtips/equations.html.

“Algebra: Expressions And Equations – Definition And Examples”. 2022. BYJUS. https://byjus.com/maths/algebra-expressions-equations/.

“Equation – Definition Of Equation, Parts, Types And Examples”. 2022. BYJUS. https://byjus.com/maths/equation/.

“Equation – Wikipedia”. 2022. en.wikipedia.org. https://en.wikipedia.org/wiki/Equation.

“Math Equation | Types Of Equations With Solution”. 2022. BYJUS. https://byjus.com/maths/math-equations/.

Samson, Ilan. “But Why? Part 7: Equations”. 2022. Medium. https://medium.com/@ilansamson_59017/but-why-part-7-1a31aef06770.

“What Is Equation? [Definition Facts & Example]”. 2022. SplashLearn – Math Vocabulary. https://www.splashlearn.com/math-vocabulary/number-sense/equation.


What is an Equation? | Don’t Memorise
What is Equation? | Definition | Explanation | Examples

In mathematics, an equation is a statement of an equality containing one or more variables. Solving the equation consists of determining which values of the variables make the equality true. Variables are also called unknowns and the values of the unknowns that satisfy the equality are called solutions of the equation. There are two kinds of equations: identities and conditional equations. An identity is true for all values of the variable. A conditional equation is true for only particular values of the variables. An equation is written as two expressions, connected by a equals sign (“=”). The expressions on the two sides of the equals sign are called the “left-hand side” and “right-hand side” of the equation.

⭐ I suggest that you read the entire reference. Other references can be read in their entirety but I leave that up to you.

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