Factors and Multiples
Key Concepts
Factors and multiples are fundamental concepts in mathematics. Factors are numbers that divide another number exactly without leaving a remainder, while multiples are the result of multiplying a number by an integer.
Factors
Factors of a number are all the numbers that divide it exactly. For example, the factors of 12 are 1, 2, 3, 4, 6, and 12 because each of these numbers divides 12 without leaving a remainder.
Example: Find the factors of 20.
Step 1: Start with 1 and 20 (since 1 and the number itself are always factors).
Step 2: Check 2: 20 ÷ 2 = 10 (no remainder), so 2 and 10 are factors.
Step 3: Check 3: 20 ÷ 3 = 6.67 (remainder), so 3 is not a factor.
Step 4: Check 4: 20 ÷ 4 = 5 (no remainder), so 4 and 5 are factors.
Step 5: Check 5: 20 ÷ 5 = 4 (already listed).
Factors of 20: 1, 2, 4, 5, 10, 20.
Multiples
Multiples of a number are the products obtained when that number is multiplied by integers. For example, the multiples of 3 are 3, 6, 9, 12, 15, etc., because these are the results of multiplying 3 by 1, 2, 3, 4, 5, etc.
Example: Find the first five multiples of 7.
Step 1: Multiply 7 by 1: 7 × 1 = 7.
Step 2: Multiply 7 by 2: 7 × 2 = 14.
Step 3: Multiply 7 by 3: 7 × 3 = 21.
Step 4: Multiply 7 by 4: 7 × 4 = 28.
Step 5: Multiply 7 by 5: 7 × 5 = 35.
First five multiples of 7: 7, 14, 21, 28, 35.
Examples and Analogies
Think of factors as the building blocks of a number. Just as a building is made up of smaller bricks, a number is made up of its factors. Multiples, on the other hand, are like the steps on a staircase. Each step is a multiple of the height of one step.
Practical Application
Understanding factors and multiples helps in various real-life situations. For example, when dividing a pizza into equal slices, you are dealing with factors. When counting items in groups, such as the number of students in a class, you are dealing with multiples.