Understanding the Law of Indices

Mathematics Primary 5 First Term Lesson Notes Week 5

Subject: Mathematics

Class: Primary 5

Term: First Term

Week: 5

Age: 10 years

Topic: The Law of Indices

Sub-topic:

  1. Raised to Power Zero
  2. Additive Law
  3. Subtractive Law

Duration: 40 minutes

Behavioural Objectives: By the end of the lesson, pupils should be able to:

  1. Understand the concept of any number raised to the power of zero.
  2. Apply the additive law of indices.
  3. Apply the subtractive law of indices.

Keywords:

  • Indices
  • Power
  • Exponent
  • Additive
  • Subtractive

Set Induction: Start the lesson with a quick review of multiplication and division of numbers.

Entry Behaviour: Pupils should already be familiar with basic multiplication and division.

Learning Resources and Materials:

  • Whiteboard and markers
  • Number cards
  • Charts showing examples of indices

Building Background/Connection to Prior Knowledge: Discuss with pupils how multiplication can be seen as repeated addition, which leads to the idea of exponents as repeated multiplication.

Embedded Core Skills:

  • Critical thinking
  • Problem-solving
  • Analytical skills

Learning Materials:

  • Whiteboard
  • Markers
  • Charts

Reference Books:

  • Lagos State Scheme of Work

Instructional Materials:

  • Number cards
  • Example charts

Content:

1. Raised to Power Zero:

Any number raised to the power of zero is equal to 1.
Example: 50 = 1

2. Additive Law (Multiplication Law):

When multiplying numbers with the same base, add their exponents.
Formula: am × an = am+n
Example: 23 × 22 = 23+2 = 25

3. Subtractive Law (Division Law):

When dividing numbers with the same base, subtract their exponents.
Formula: am ÷ an = am-n
Example: 45 ÷ 42 = 45-2 = 43

Evaluation

  1. 70 = ____
    a. 0 b. 7 c. 1 d. 49
  2. 32 × 33 = ____
    a. 36 b. 35 c. 39 d. 31
  3. 104 ÷ 102 = ____
    a. 102 b. 103 c. 106 d. 101
  4. 51 = ____
    a. 5 b. 1 c. 0 d. 25
  5. 23 × 22 = ____
    a. 26 b. 24 c. 25 d. 21
  6. 60 = ____
    a. 0 b. 1 c. 6 d. 36
  7. 92 × 93 = ____
    a. 95 b. 96 c. 99 d. 98
  8. 40 = ____
    a. 4 b. 0 c. 1 d. 16
  9. 23 × 22 = ____
    a. 25 b. 26 c. 24 d. 27
  10. 34 ÷ 32 = ____
    a. 36 b. 32 c. 31 d. 34

Conclusion:

  • The teacher goes around to mark and provides necessary feedback on the topic.

 

70 = ____
a. 0
b. 7
c. 1
d. 49

32 × 33 = ____
a. 36
b. 35
c. 39
d. 31

104 ÷ 102 = ____
a. 102
b. 103
c. 106
d. 101

51 = ____
a. 5
b. 1
c. 0
d. 25

23 × 22 = ____
a. 26
b. 24
c. 25
d. 21

60 = ____
a. 0
b. 1
c. 6
d. 36

92 × 93 = ____
a. 95
b. 96
c. 99
d. 98

40 = ____
a. 4
b. 0
c. 1
d. 16

24 ÷ 21 = ____
a. 25
b. 23
c. 24
d. 22

82 ÷ 80 = ____
a. 82
b. 80
c. 81
d. 82

53 ÷ 52 = ____
a. 55
b. 51
c. 56
d. 52

(24 × 23) ÷ 22 = ____
a. 25
b. 26
c. 27
d. 24

75 × 70 = ____
a. 75
b. 70
c. 71
d. 76

33 × 32 = ____
a. 35
b. 34
c. 36
d. 33

100 ÷ 101 = ____
a. 100
b. 10-1
c. 101
d. 101

 

What is the value of any number raised to the power of zero?
Any number raised to the power of zero equals 1.
Example: 70 = 1

What does the additive law of indices state?
The additive law states that when multiplying numbers with the same base, you add the exponents.
Formula: am × an = am+n

What is the result of 23 × 22?
According to the additive law, 23 × 22 = 23+2 = 25

What does the subtractive law of indices describe?
The subtractive law states that when dividing numbers with the same base, you subtract the exponents.
Formula: am ÷ an = am-n

What is the result of 54 ÷ 52?
According to the subtractive law, 54 ÷ 52 = 54-2 = 52

What does 30 equal?
Any number raised to the power of zero equals 1.
Example: 30 = 1

How do you simplify 85 × 83?
According to the additive law, 85 × 83 = 85+3 = 88

What is the result of 67 ÷ 64?
According to the subtractive law, 67 ÷ 64 = 67-4 = 63

What does 100 × 103 equal?
According to the additive law, 100 × 103 = 100+3 = 103

How do you simplify 26 ÷ 23?
According to the subtractive law, 26 ÷ 23 = 26-3 = 23

What is the result of 90?
Any number raised to the power of zero equals 1.
Example: 90 = 1

What is the formula for multiplying numbers with different bases?
The law of indices does not apply to different bases; it only applies when the bases are the same.

What does the term ‘base’ refer to in indices?
The base is the number that is raised to a power.
Example: In 43, 4 is the base.

How do you express 75 ÷ 72 in simplified form?
According to the subtractive law, 75 ÷ 72 = 75-2 = 73

What is the result of 32 × 30?
According to the additive law, 32 × 30 = 32+0 = 32