Algebraic Techniques Revision

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Variable: A letter that represents an unknown number

Substitution: Replacing a variable with a given value

Like terms: Terms with the same variables including powers

Like terms:

  • 3x and 7x
  • 2y² and 5y²
  • 7xy and 4yx (why?)

Unlike terms:

  • 3x and 4y
  • 2x and 5x²

Quick Revision: Variables and substitution

If x = 5, what is the value of:

3x =

2x + 1 =

x² =

4x - 3 =

x + 8 =

2x² =

Diagnostic Quiz 1: Substitution

Your turn (silent)

If a = 3 and b = 4, find:

  1. 2a =

  2. 3b - 5 =

  3. a + b =

  1. ab =

  2. a² + b =

  3. 2a + 3b =

Like Terms vs Unlike Terms

Like terms have the same variable AND the same power

Unlike terms have different variables OR different powers

Examples:

  • 3x and 7x are like terms
  • 2y² and 5y² are like terms
  • 3x and 4y are unlike terms (different variables)
  • 2x and 5x² are unlike terms (different powers)

Sorting Practice: Like or Unlike?

Pair 1: 4x and 9x

Pair 2: 3y and 2z

Pair 3: 7a² and 5a²

Pair 4: 2m and 8m³

Pair 5: 6p and 11p

Pair 6: 4t² and 7t

Pair 7: 3k and k

Pair 8: 5xy and 2xy

Adding Like Terms

When adding like terms, add the coefficients (numbers) and keep the variable part the same.

Examples:

  • 3x + 5x = 8x
  • 2y² + 7y² = 9y²
  • 4a - a = 3a (remember a = 1a)

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Diagnostic Quiz 2: Adding Like Terms

Your turn (silent)

Simplify by adding like terms:

  1. 2x + 7x =

  2. 5y - 3y =

  3. a + 4a =

  4. 6m² + 2m² =

  1. 8p - p =

  2. 3t² - t² =

  3. 4k + k + 2k =

  4. 9n - 5n + n =

Mixed Expression Practice

When expressions have unlike terms, we cannot add them together.

Examples:

  • 3x + 2y cannot be simplified (different variables)
  • 4a + 5a² = 4a + 5a² (different powers)
  • 2p + 3p + 4q = 5p + 4q (collect the like terms only)

Simplify: 2x + 3y + 5x =

Simplify: 4a² + 2a + 3a² =

Simplify: 7m + 2n - 3m =

Simplify: 5k² + k + 2k² =

NATURAL BREAK POINT

End of Lesson 1 Optionn

Multiplying Algebraic Terms

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When multiplying: - Multiply the numbers - Multiply the variables (add the powers)

Examples:

  • 3 × 2x = 6x
  • 4a × 5 = 20a
  • 2x × 3x = 6x² (because x × x = x²)
  • 5y² × 2y = 10y³ (because y² × y = y³)

Multiplication Practice

3 × 4x =

5y × 2 =

2a × 3a =

4x × x =

6 × 2m =

3p × 4 =

5t × 2t =

y × 7y =

Dividing Algebraic Terms

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When dividing: - Divide the numbers - Divide the variables (subtract the powers)

Examples:

  • 6x ÷ 2 = 3x
  • 12a ÷ 4a = 3 (because 12 ÷ 4 = 3 and a ÷ a = 1)
  • 8x² ÷ 2x = 4x (because 8 ÷ 2 = 4 and x² ÷ x = x)

Division Practice

8x ÷ 4 =

10y ÷ 5y =

12a² ÷ 3a =

15m ÷ 3 =

6p ÷ 2 =

14t ÷ 7t =

20x² ÷ 4x =

18n ÷ 6 =

Diagnostic Quiz 3: Multiplication & Division

Your turn (silent)

Calculate: - 3 × 5x = - 4y × 2y = - 12a ÷ 3 = - 8x ÷ 2x =

Calculate: - 6 × 2m = - 3p × 4p = - 15t ÷ 5 = - 10y ÷ 5y =

Calculate: - 2 × 7k = - 5n × 3n = - 18x ÷ 6 = - 12a ÷ 4a =

Mixed Practice: All Skills

  1. If x = 4, find 3x + 5 =

  2. Simplify: 2a + 5a - a =

  3. Calculate: 3y × 4y =

  4. Simplify: 7m + 2n + 3m =

  1. Calculate: 15x ÷ 3 =

  2. If y = 2, find y² + 3y =

  3. Simplify: 4p² + 2p² - p² =

  4. Calculate: 6a ÷ 2a =

Extension Challenge

For students who finish early:

  1. If a = 3 and b = 2, find the value of 2a² + 3ab - b²

  2. Simplify completely: 4x + 2y + 3x² + 5x - y + x²

  3. Calculate: (3x × 2y) ÷ x

  4. If p = 5, which expression has the largest value?

    • 2p + 1
    • p² - 3
    • 3p - 4

Lesson Summary

Today we revised:

Variables & Substitution: Replacing letters with numbers

Like Terms: Same variable, same power - can be added/subtracted

Unlike Terms: Different variables or powers - cannot be combined

Multiplication: Multiply numbers, add powers of variables

Division: Divide numbers, subtract powers of variables

Homework/Next Steps

Based on today’s diagnostics:

If students struggled with substitution: Practice basic substitution problems

If students struggled with like terms: More practice identifying and combining like terms

If students struggled with multiplication/division: Review the rules and practice simple examples

If students mastered everything: Move on to expanding brackets next lesson