Exponent of a number shows how many times we are multiplying a number by itself. For example, 34 means we are multiplying 3 four times. Its expanded form is 3×3×3×3. Exponent is also known as the power of a number. It can be a whole number, fraction, negative number, or decimals. Let's learn more about exponents in this lesson.
|1.||What are Exponents?|
|5.||Scientific Notation with Exponents|
|6.||Laws (Properties or Rules) of Exponents|
What are Exponents?
The exponent of a number shows how many times the number is multiplied by itself. For example, 2×2×2×2 can be written as 24, as 2 is multiplied by itself 4 times. Here, 2 is called the "base" and 4 is called the "exponent" or "power." In general, xn means that x is multiplied by itself for n times.
Here, in the term xn,
- x is called the "base"
- n is called the "exponent" or "power"
- xn is read as "x to the power of n" (or) "x raised to n"
Examples of Exponents
Some examples of exponents are as follows:
- 3 × 3 × 3 × 3 × 3 = 35
- -2 × -2 × -2 = (-2)3
- a × a × a × a × a × a = a6
Why are Exponents Important?
Exponents are important because, without them, the products where a number is repeated by itself many times is very difficult to write. For example, it is very easy to write 57 instead of writing 5 × 5 × 5 × 5 × 5 × 5 × 5.
A negative exponent tells us how many times we have to multiply the reciprocal of the base. For example, if it is given that a-n, it can be expanded as 1/an. It means we have to multiply the reciprocal of a, i.e 1/a 'n' times. Negative exponents are used to write fractions with exponents. Some of the examples of negative exponents are 2 × 3-9, 7-3, 67-5, etc. To learn more about negative exponents, click here.
If an exponent of a number is a fraction, it is known as a fractional exponent. Square roots, cube roots, nth root are all parts of fractional exponents. Number with power 1/2 is termed as the square root of the base. Similarly, numbers with power 1/3 is called cube root of the base. Some examples of fractional exponents are 52/3, -81/3, 105/6, etc. To learn more about fractional exponents, click here.
If an exponent of a number is given in the decimal form, it is known as a decimal exponent. It is slightly difficult to evaluate the correct answer of any decimal exponent so we find the approximate answer for such cases. Decimal exponents can be solved by first converting the decimal in fraction form. For example, 41.5 can be written as 43/2 which can be simplified further to get the final answer 8 or -8.
Scientific Notation with Exponents
Scientific notation is the standard form of writing very large numbers or very small numbers. In this, numbers are written with the help of decimal and powers of 10. A number is said to be written in scientific notation when a number from 0 to 9 is multiplied by a power of 10. In the case of a number greater than 1, the power of 10 will be a positive exponent, while in the case of numbers less than 1, the power of 10 will be negative. Let's understand the steps for writing numbers in scientific notation:
- Step 1: Put a decimal point after the first digit of the number from the right. If there is only one digit in a number excluding zeros, then we don't need to put decimal.
- Step 2: Multiply that number with a power of 10 such that the power will be equal to the number of times we shift the decimal point.
By following these two simple steps we can write any number in standard form with exponents, for example, 560000 = 5.6 × 105, 0.00736567 = 7.36567 × 10-3.
To learn more about the use of exponents in writing scientific notation of numbers, visit the following articles:
- How Do You Write 2.5 million in Scientific Notation?
- How do you write 12 million in scientific notation?
- How do you write 0.0001 in scientific notation?
- What is the scientific notation for 8 million?
- How do you write 13 million in scientific notation?
- Which of the following expressions is written in scientific notation
Laws (Properties or Rules) of Exponents
The laws (properties or rules) of exponents are used to solve problems involving exponents. The laws of exponents are mentioned below.
- Law of Product: am × an = am+n
- Law of Quotient: am/an = am-n
- Law of Zero Exponent: a0 = 1
- Law of Negative Exponent: a-m = 1/am
- Law of Power of a Power: (am)n = amn
- Law of Power of a Product: (ab)m = ambm
- Law of Power of a Quotient: (a/b)m = am/bm
To learn more about exponent rules, click here.
Tips and Tricks:
- If a fraction has a negative exponent, then we take the reciprocal of the fraction to make the exponent positive. i.e., (a/b)-m = (b/a)m.
- When the exponents are the same, we can set the bases equal and vice versa. i.e., am = an ⇔ m = n.
Solved Examples on Exponents
Example 1: The dimensions of a wardrobe are x5 units, y3 units, and x8 units. Find its volume.
The dimensions of the wardrobe are length= x5 units, width= y3 units and heigth= x8 units. The volume of the wardrobe is, volume= lwh. So, by substituting the values, the volume of the wardrobe is x5 × y3 × x8= x13y3. Therefore, the volume of the wardrobe is x13y3 cubic units.
Example 2: In a forest, each tree has about 57 leaves and there are about 53 trees in the forest. Find the total number of leaves.
The number of trees in the forest = 53 and the number of leaves in each tree = 57. The total number of leaves are: 53 × 57 = 510 (because am × an = a(m+n)). Therefore, the total number of leaves is 510.
Practice Questions on Exponents
FAQs on Exponents
What are the Laws of Exponents?
Laws of exponents are some rules that we use to do calculations involving exponents. These rules help us to calculate quickly. Laws of exponents are given below:
- am × an = am+n
- am/an = am-n
- a0 = 1
- a-m = 1/am
- (am)n = amn
- (ab)m = ambm
- (a/b)m = am/bm
What are the Examples of Exponents?
Some examples of exponents are as follows:
- 3 × 3 × 4 × 4 × 4 = 32 × 43
- -2 × -2 × -2 × -2 = (-2)4
- a × a × a × a × a = a5
How do Exponents Relate to Real Life?
In real life, we use the concept of exponents to write numbers in a simplified manner and in a short way. Repeated multiplication can be easily written with the help of exponents. Also, we use exponents to write larger numbers, for example, the distance of moon from earth, the number of bacteria present on a surface, etc.
How to Add Exponents?
Exponents cannot be added. We can only add like terms (terms having the same exponent and same variable). But, in the case of the multiplication of terms with the same variables, we add the exponents of the variable to multiply. For example, 3x2 × x4 = 3x6.
Why are Exponents Important?
Exponents are important to write the values of numbers in simplified form. We know that repeated addition can be written as multiplication. In the same way, repeated multiplication can be written simply with the help of exponents.
How are Negative Exponents Used in Real Life?
Negative exponents are used to write very small numbers in real life, which means numbers having values between 0 to 1.
What is Zero Exponent?
Zero exponent means numbers that have 0 as their exponent. The values of those numbers are always 1. Any number with 0 as its exponent is equal to 1.