Understanding exponents
Key Notes:
1. What are Exponents?
- An exponent refers to the number of times a number (called the base) is multiplied by itself.
- It is written in the form: a^n, where:
- a is the base.
- n is the exponent (or power).
2. Basic Terminology
- Base: The number being multiplied.
- Exponent: The number showing how many times the base is used as a factor.
- Example: In 3^4, 3 is the base, and 4 is the exponent. This means 3 × 3 × 3 × 3 = 81.
3. Understanding Powers of 10
- Exponents are commonly used with the base 10 to represent large or small numbers.
- Example: 10^3 = 10 × 10 × 10 = 1000.
4. Exponent Rules
- Product Rule: When multiplying two numbers with the same base, add the exponents.
- Example: a^m × a^n = a^(m+n).
- Example: 2^3 × 2^2 = 2^(3+2) = 2^5 = 32.
- Quotient Rule: When dividing two numbers with the same base, subtract the exponents.
- Example: a^m ÷ a^n = a^(m−n).
- Example: 5^6 ÷ 5^2 = 5^(6-2) = 5^4 = 625.
- Power Rule: When raising an exponent to another exponent, multiply the exponents.
- Example: (a^m)^n = a^(m×n).
- Example: (2^3)^2 = 2^(3×2) = 2^6 = 64.
- Zero Exponent Rule: Any non-zero number raised to the power of 0 is equal to 1.
- Example: a^0 = 1 (if a ≠ 0).
- Negative Exponent Rule: A number with a negative exponent represents the reciprocal of the number raised to the positive exponent.
- Example: a^(-n) = 1/a^n.
- Example: 2^(-3) = 1/2^3 = 1/8.
5. Working with Large and Small Numbers
Exponents make it easier to express large or small numbers in scientific notation.
Example: 3 × 10^6 represents 3,000,000.
Learn with an example
Write the expression using exponents.
42 · 42 · 42 · 59
Start with the given expression.
42 · 42 · 42 · 59
Write the 42’s using exponents. 42 is used as a factor 3 times, so its exponent is 3.
423
Write the 59’s using exponents. 59 is used as a factor 1 time, so its exponent is 1. When a number has an exponent of one, you don’t need to write the exponent.
423 · 59
Write the expression using exponents.
7 · 7 · 7
Start with the given expression.
7 · 7 · 7
Write the 7’s using exponents. 7 is used as a factor 3 times, so its exponent is 3.
73
Write the expression using exponents.
33 · 33 · 58 · 58 · 58
Start with the given expression.
33 · 33 · 58 · 58 · 58
Write the 33’s using exponents. 33 is used as a factor 2 times, so its exponent is 2.
332
Write the 58’s using exponents. 58 is used as a factor 3 times, so its exponent is 3.
332 · 583
Let’s practice!🖊️