Exponent

We often read numbers in words such as hundred, thousands, lakhs, crores and so on. What numbers have more digits than we can read? For example, the mass of Earth is 5972190000000000000000000 kg. This cannot be read in simple words. Thus, to pronounce these types of numbers we make use of exponents. In this article, a brief introduction of exponents is given along with rules, properties and examples.

Table of Contents:

Exponent Meaning

Exponent is defined as the method of expressing large numbers in terms of powers. That means, exponent refers to how many times a number multiplied by itself. For example, 6 is multiplied by itself 4 times, i.e. 6 × 6 × 6 × 6. This can be written as 64. Here, 4 is the exponent and 6 is the base. This can be read as 6 is raised to power 4.

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Exponent Symbol

The symbol used for representing the exponent is ^. This symbol (^) is called a carrot. For example, 4 raised to 2 can be written as 4^2 or 42. Thus, 4^2 = 4 × 4 = 16. The below table shows the representation of a few numerical expressions using exponents.

Expression Exponent representation
9 × 9 × 9 × 9 94, Base =  9, Exponent = 4
7 × 7 × 7 × 7 × 7 × 7 × 7 77, Base = 7, Exponent = 7
2 × 2 × 2 23, Base = 2, Exponent = 3

Exponent Laws

Different laws of exponents are described based on the powers they bear.

Multiplication Law: Bases – multiplying the like ones; add the exponents and keep the base the same.

When bases are raised with power to another, multiply the exponents and keep the base the same.

Division Law: Bases – dividing the like ones; subtract the exponent of the denominator from the exponent of the numerator Exponent and keep the base the same.

Let ‘a’ be any integer or a decimal number and ‘m’, ‘n’ are positive integers, that represent the powers to the bases such that the above laws can be written as:

  • am. an = am+n
  • (am)n = amn
  • (ab)n = an bn
  • (a/b)n = an/bn
  • am/an = am-n
  • am/an = 1/an-m

These laws referred to the properties of exponents. These are used to simplify complex algebraic expressions and write large numbers in an understandable manner.

Exponent and Powers

As defined above, the exponent defines the number of times a number is multiplied by itself. The power is an expression that shows repeated multiplication of the same number or factor. For example, in the expression 64, 4 is the exponent and 64 is called the 6 power of 4. That means, 6 is multiplied by itself 4 times.

Learn more about exponents and powers here.

Video Lesson

Watch The Below Video To Understand Exponents

Exponent Formula and Rules

Exponents have certain rules which we apply in solving many problems in maths. Some of the exponent rules are given below.

Zero rule: Any number with an exponent zero is equal to 1.

Example: 80 = 1, a0 = 1

One Rule: Any number or variable that has the exponent of 1 is equal to the number or variable itself.

Example: a1 = a, 71 = 1

Negative Exponent Rule: If the exponent value is a negative integer, then we can write the number as:

a-k = 1/ak

Example: 3-2 = 1/32 = 1/(3 × 3) = 1/9

Exponent Table

The below table shows the values of different expressions in terms of exponents along with their expansions and values. This will help you in understanding the simplification of numbers with exponents in detail.

Type of Exponent Expression Expansion Simplified value
Zero exponent 60 1 1
One exponent 41 4 4
Exponent and power 23 2 × 2 × 2 8
Negative exponent 5-3 1/53 = 1/(5 × 5 × 5) 1/125
Rational exponent 91/2 √9 3
Multiplication 32 × 33 3(2 + 3) = 35 273
Quotient 75/ 73 7(5 – 3) = 72 49
Power of exponent (82)2 8(2 × 2) = 84 4096

Solved Examples

Example 1: Simplify (32 × 3-5)/ 9-2

Solution:

(32 × 3-5)/ 9-2 = 3(2 – 5) × 92

= 3-3 × (32)2

= 3-2 × 34

= 3(-2 + 4)

= 32

= 9

Therefore, Simplify (32 × 3-5)/ 9-2 = 9

Example 2: Simplify and write the answer in exponential form. 

(i) (25 ÷ 28 )5 × 2-5 

(ii) (– 4)-3 × (5)-3 × (–5)-3 

(iii) (1/8) × (3)-3

Solution:

(i) (25 ÷ 28 )5 × 2-5 

= (25-8)5 × 2-5 

= (2-3)5 × 2-5 

= 2(-15 – 5)

= 2-20

Or

= 1/(2)20

(ii) (– 4)-3 × (5)-3 × (–5)-3 

= [(– 4) × 5 × (–5)]-3 

= [100]-3

(iii) (1/8) × (3)-3

= [1/(2)3] × (3)-3

= 2-3 × 3-3

= (2 × 3)-3

= 6-3

Practice Problems

  1. Find m such that (-4)m + 1 × (-4)5 = (-4)7.
  2. Find the value of (50 + 4-1) × 22.
  3. Expand the following numbers using exponents.
    (i) 1025.63
    (ii) 1256.249

To learn more about exponents and other maths-related concepts, download BYJU’S – The Learning App today!

Frequently Asked Questions on Exponent

Q1

What is an Exponent?

Exponent is the method of expressing large numbers in terms of powers. For example, 5 multiplied 3 times, i.e. 5 × 5 × 5 can be expressed as 5^3, where 3 is the exponent of 5.
Q2

How do you express the number with a rational exponent?

Consider a number with a rational exponent as 16^{1/2}. This can be expressed as:
16^{1/2} = √16 = 4
Q3

What is 2 with an exponent of 4?

2 with an exponent of 4 can be written as 2^4 and its value is 2 × 2 × 2 × 2 = 16.
Q4

How do you write the negative exponent rule?

If the exponent value is a negative integer, then the number can be expressed as:
a^{-k} = 1/a^k
This is the negative exponent rule.
Q5

What is the zero exponent rule?

Zero exponent rule states that any number with an exponent zero (0) is equal to 1.