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Factors and multiples

Factors and multiples

Factors are the numbers that can be multiplied together to get another number. For example, the factors of 12 include 1, 2, 3, 4, 6, and 12, because all these numbers can divide 12 without leaving a remainder.

Multiples are the result of multiplying a number by an integer. For instance, the multiples of 3 include 3, 6, 9, 12, and so on, which are obtained by multiplying 3 by 1, 2, 3, 4, etc.

In summary, factors are what you multiply together to achieve a number, while multiples are what you get when you multiply a number by integers.

Part 1: Understanding factor pairs

Use multiplication and an understanding of area to identify factor pairs for 6 and 16.

Sure! Here are the key points to learn when studying "Understanding Factor Pairs":

  1. Definition of Factor Pairs: Factor pairs are two numbers that, when multiplied together, yield a specific product.

  2. Identifying Factor Pairs: To find the factor pairs of a number, identify all the pairs of integers that multiply to that number.

  3. Using Factor Trees: Factor trees can be helpful in breaking down a number into its prime factors, which can then be used to find all its factor pairs.

  4. Properties of Factor Pairs:

    • Every number has at least one factor pair (1 and the number itself).
    • Factor pairs exist in positive and negative forms.
  5. Finding Factor Pairs Efficiently: To find factor pairs, only check for factors up to the square root of the number; for each factor found, its pair can be calculated by dividing the number by that factor.

  6. Applications of Factor Pairs: Understanding factor pairs is essential in solving problems related to multiplication, division, and simplifying fractions.

  7. Practice: Regular practice in identifying factor pairs through exercises enhances proficiency and understanding.

  8. Relation to Prime Factorization: Recognizing the connection between factor pairs and prime factorization can deepen understanding of number properties.

By mastering these points, learners will have a solid understanding of factor pairs and their significance in mathematics.

Part 2: Finding factors of a number

Sal finds the factors of 120.

Here are the key points to learn when studying "Finding factors of a number":

  1. Definition of Factors: Factors are whole numbers that divide a given number evenly, without leaving a remainder.

  2. Identifying Factors: To identify factors, divide the number by whole numbers starting from 1 up to the number itself, checking which divisions result in whole numbers.

  3. Factor Pairs: Factors come in pairs. For each factor less than the square root of the number, there is a corresponding factor greater than the square root.

  4. Prime Factors: Prime factors are the factors of a number that are prime numbers. Use factor trees or the division method to find them.

  5. Understanding Multiples and Divisibility: Knowing the multiples of a number can help in identifying its factors. A number is a factor of another if it divides it without leaving a remainder.

  6. Common Factors: Common factors are factors that two or more numbers share. This is important for simplifying fractions and finding the greatest common divisor (GCD).

By mastering these concepts, one can effectively determine the factors of any given number.

Part 3: Reasoning about factors and multiples

Use the equation 3x5=15 to understand the relationship between factors and multiples.

When studying "Reasoning about factors and multiples," focus on the following key points:

  1. Definitions:

    • Factors: Whole numbers that divide another number exactly without leaving a remainder.
    • Multiples: The result of multiplying a number by an integer.
  2. Identifying Factors:

    • Use factor pairs to find all factors of a number.
    • Recognize that every number has at least two factors: 1 and itself.
  3. Identifying Multiples:

    • List multiples of a number by multiplying it by whole numbers (e.g., 2, 4, 6 for the number 2).
    • Understand that a multiple is always equal to or greater than the original number.
  4. Prime and Composite Numbers:

    • Understand the distinction between prime numbers (numbers with exactly two factors: 1 and themselves) and composite numbers (numbers with more than two factors).
  5. Greatest Common Factor (GCF):

    • Learn methods to find the GCF of two or more numbers (list factors, prime factorization, or using the Euclidean algorithm).
  6. Least Common Multiple (LCM):

    • Explore methods to find the LCM (list multiples, prime factorization, or using the intersection of multiples).
  7. Divisibility Rules:

    • Familiarize yourself with simple rules for determining divisibility by numbers like 2, 3, 5, 10, etc.
  8. Application Problems:

    • Practice solving word problems that require understanding factors and multiples in real-life contexts.
  9. Number Patterns:

    • Recognize patterns in factors and multiples, including sequences and relationships.

By mastering these points, you'll develop a strong understanding of factors and multiples, essential for more advanced topics in mathematics.

Part 4: Finding factors and multiples

Sal uses divisibility rules to determine if numbers are factors of 154 and then finds multiples of 14.

Here's a summary of key points for studying "Finding Factors and Multiples":

Factors:

  1. Definition: Factors are whole numbers that can be multiplied together to produce another number.
  2. Finding Factors:
    • Start with 1 and the number itself.
    • Test integers sequentially to see if they divide the number without leaving a remainder.
  3. Prime Factors:
    • Factors that are prime numbers; can be found using methods like factor trees or the division method.
  4. Greatest Common Factor (GCF):
    • The largest factor that two or more numbers share.
    • Methods to find GCF include listing factors, prime factorization, and using the Euclidean algorithm.

Multiples:

  1. Definition: Multiples are the results of multiplying a number by whole numbers (1, 2, 3, etc.).
  2. Finding Multiples:
    • Multiply the number by whole numbers to generate its multiples.
  3. Least Common Multiple (LCM):
    • The smallest multiple that two or more numbers have in common.
    • Methods to find LCM include listing multiples, prime factorization, and using the GCF.

Strategies:

  • Use division to check for factors efficiently.
  • Employ systematic listing and prime factorization for both GCF and LCM.
  • Understand relationships between factors and multiples for problem-solving.

These concepts form the foundation for understanding factors and multiples in mathematics.

Part 5: Identifying multiples

Use skip counting and division to identify multiples of 9.

When studying "Identifying Multiples," key points include:

  1. Definition of Multiples: A multiple of a number is the product of that number and an integer. For example, the multiples of 3 are 3, 6, 9, 12, etc.

  2. Finding Multiples: To find multiples of a number, simply multiply the number by integers (1, 2, 3, 4, ...).

  3. Identifying Patterns: Observing patterns in multiples can help in recognizing growth (e.g., multiples of 5 end in 0 or 5).

  4. Use of Number Lines: A number line can visually represent multiples, aiding in understanding their spacing and frequency.

  5. Application in Word Problems: Multiples are used to solve problems involving equal groups or arrays.

  6. Common Multiples: The least common multiple (LCM) is the smallest multiple shared by two or more numbers.

  7. Prime Numbers: Understanding prime numbers is important as they have only two multiples (1 and the number itself).

  8. Practice: Regular exercises in identifying multiples strengthen understanding and improve speed.

Mastering these points will enhance your ability to work with multiples efficiently.