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Mental Math in the Classroom

Mental Math in the Classroom

Mental Math in the Classroom 150 150 SchoolTutoring.Staff

Mental math is the act of performing calculations in one’s head without the assistance of an external device such as a calculator or an abacus. In this article, the calculations and the applications of mental math in different areas of mathematics will be discussed.

For Which Types of Calculations is Mental Math Used?

The most common way in which mental math is used is to perform the four basic arithmetic operations, that is, addition, subtraction, multiplication and division. The multiplication tables for numbers from one to ten are mandatory for elementary school students, so many students are already very comfortable with multiplying small numbers, and by extension, they are also familiar with dividing those numbers as well. Many students in high school also memorize the squares of numbers, typically from one to twenty, to facilitate operations such as completing the square or rationalizing denominators.

Applications of Mental Math in the Classroom

In high school, one of the most frequently tested concepts is factoring, the act of splitting a polynomial into its many factors.  The biggest roadblock for students when they try to factor, however, is when they have to quickly try many combinations of numbers to multiply and add, and because of the lack of mental math in their previous teachings, they find this concept very hard. With mental math, these students would have found these questions rather simple, but because of their aversions to performing calculations in their head, they write off high school math as a subject in which they cannot excel. This is one of the most important reasons why mental math is important in the classroom. Many other subjects, such as logarithms, are greatly simplified with an aptitude to perform mental math.

Applications of Mental Math in the Real World

Many common daily interactions involve mental math, and most people who are proficient at this do not realize that they are using it every day. For example, to calculate the cost of goods after tax, one might use mental math to estimate how much something will cost, so that one does not attempt to buy more than they can pay for. Another example is when multiple people split a bill, it is easy to estimate how much each person will have to pay by performing a rudimentary division problem. One of the best applications of mental math is when one has to convert between different units, a common operation when many products such as rulers or measuring cups use different units to denote the same quantity, such as using liters or fluid ounces for volume.


Mental math is extremely important and many people often take it for granted.  Mental math not only simplifies high school mathematics, but also many day to day interactions in the real world. So take out your calculator, and say “Calc you later!”