What Does “Of” Mean in Math: Meaning, Usage, Misconceptions, & Tips 

What does “of” mean in math? This is a common question that many newbie math students encounter when dealing with fractions, percentages, ratios, and other mathematical expressions.

​​You might have seen it in expressions like 3/4 of a pizza, 50% of a number, or the square root of 16. But what does it actually mean, and how can you use it to solve problems? 

In this article, you will discover the meaning of “of” in math and how it relates to fractions, percentages, and other operations. I will also use examples to help you understand and practice your skills. 

By the end of this article, you will have a clear understanding of what “of” means in math and how to apply it in different situations.

The meaning of “of” in math

In general, “of” in math means “times” or “multiplied by.” For example, when we say “half of 10”, we mean “half times 10” or “0.5 x 10”, which is 5. Similarly, when we say “25% of 200”, we mean “25% times 200” or “0.25 x 200”, which is 50.

However, there are some exceptions to this rule. For example, when we say “the square root of 16”, we do not mean “the square root times 16”, but rather, it implies the number that, when multiplied by itself, gives 16. 

In this case, “of” means “that satisfies the condition of”. Another example is when we say “the sum of 3 and 4”, we do not mean “the sum times 3 and 4”, but rather “the result of adding 3 and 4”. In this case, “of” means “that results from the operation of”.

Therefore, to determine the meaning of “of” in math, it is imperative to look at the context and the type of expression that it is used in. Sometimes, it may be helpful to rewrite the expression using parentheses or symbols to clarify the meaning.

The usage of “of” in math

Now that you know the meaning of “of” in math let”‘s look at some examples of how to use it correctly. Here are some common scenarios where “of” is used in math:

  • To express a fraction or a percentage of a whole. For example, “one-third of 12” means “one-third times 12” or “(1/3) x 12”, which is 4. Similarly, “40% of 120” means “40% times 120”, or “(40/100) x 120”, which is 48.
  • To express a ratio or a proportion of two quantities. For example, “the ratio of boys to girls in a class is 3 to 2” means “the fraction of boys in the class is 3/5, and the fraction of girls in the class is 2/5”. Similarly, “the proportion of red balls to blue balls in a box is 4 to 1,” means “the fraction of red balls in the box is 4/5, and the fraction of blue balls in the box is 1/5”.

Tips for understanding and applying “of” in math

meaning of "of" in math

There are several mathematical symbols in math, and it’s crucial to learn how to use them. Here are some tips to help you understand and apply “of” in math:

  • Pay attention to the context and the type of expression that “of” is used. Sometimes, it may be helpful to rewrite the expression using parentheses or symbols to clarify the meaning.
  • Remember that “of” usually means “times” or “multiplied by” unless it is used in expressions that involve square roots, sums, differences, products, quotients, powers, etc.
  • When dealing with fractions, percentages, ratios, or proportions that involve “of,” you can use cross-multiplication or equivalent fractions to simplify or solve them. For example, to find out what fraction of 15 is 9, you can write: x/15 = 9/15 and cross-multiply: x = (9 x 15)/15 = 9. Similarly, to find out what percentage of 80 is 20, you can write: x/100 = 20/80, and cross-multiply: x = (20 x 100)/80 = 25.

Are there misconceptions about the usage of “of” in math?

One of the common misconceptions about the usage of “of” in math is that it always means multiplication. For example, some students may think that 50% of 20 is the same as 50 x 20, which is incorrect. 

The word “of” can have different meanings depending on the context and the type of mathematical expression. Sometimes, “of” can mean a part of a whole, such as in fractions or percentages. 

Other times, “of” can mean a function applied to an argument, such as in logarithms or trigonometry. Therefore, it is important to understand the meaning of “of” in each situation and apply the appropriate operation or rule.


What is the fundamental role of “of” in mathematics?

In mathematics, “of” serves as a connector, indicating relationships, quantities, and associations between different elements in mathematical expressions.

How does “of” differ from “in” in mathematical contexts?

While both terms are prepositions, “of” signifies possession or association, whereas “in” denotes location or inclusion within a set.

What is the difference between “of” and “off” in math?

When dealing with mathematical expressions, it’s essential to use “of” to express relationships and operations accurately. In contrast, “off” is not a conventional term within the formal mathematical discourse. However, it is used in the context of discount or reduction. For example, round off a number to the nearest tens, thousands, etc. 

What are the real-world examples of the application of “of” in mathematics?

Yes. In percentage calculations, the term “of” is used to express a portion of a whole, making it essential in determining proportions.


You’ve reached the end of this article on what does “of” mean in math. I hope you enjoyed reading it and learned something new. “Of” is a word that can have different meanings depending on the context, but in math, it usually means multiplication or a fraction. 

To find out what “of” means in a math problem, you can always replace it with a multiplication sign and see if it makes sense. Remember, math is a language that you can use to communicate ideas and solve problems. 

You can also learn more about proven strategies to get better at math.

The more you practice, the more fluent you will become. Thank you for reading, and happy learning.