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JSS2: MATHEMATICS - 1ST TERM

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  1. Properties of Whole Numbers I | Week 1
    4 Topics
    |
    1 Quiz
  2. Properties of Whole Numbers II | Week 2
    4 Topics
    |
    1 Quiz
  3. Properties of Whole Numbers III | Week 3
    5 Topics
    |
    1 Quiz
  4. Indices | Week 4
    2 Topics
    |
    1 Quiz
  5. Laws of Indices | Week 5
    5 Topics
    |
    1 Quiz
  6. Whole Numbers & Decimal Numbers | Week 6
    4 Topics
    |
    1 Quiz
  7. Standard Form | Week 7
    3 Topics
    |
    1 Quiz
  8. Significant Figures (S.F) | Week 8
    4 Topics
    |
    1 Quiz
  9. Fractions, Ratios, Proportions & Percentages I | Week 9
    6 Topics
    |
    1 Quiz
  10. Fractions, Ratios, Proportions & Percentages II | Week 10
    4 Topics
    |
    1 Quiz
  11. Fractions, Ratios, Proportions & Percentages III | Week 11
    3 Topics
    |
    1 Quiz
  12. Approximation & Estimation | Week 12
    1 Topic
    |
    1 Quiz
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Topic Content:

  • Meaning of Index Number
  • Worked Examples

What is an Index Number?

An index is the number of times a given number has been multiplied by itself.

For example:

5 × 5 × 5 × 5 × 5 × 5  =  56,  ‘5’  has been multiplied by itself 6 times.

5 is the base number and 6 is the index or power 

Screenshot 2023 08 20 at 06.13.05

The plural of index is indices.

Worked Example 4.1.1:

Write the following in index form 

a. 5 × 5 × 5
b. 2 × 2 × 2 × 2 × 2
c. 3 × 3 × 3 × 3
d. 128
e. 81

Solution

a. 5 × 5 × 5 = 53

b. 2 × 2 × 2 × 2 × 2 = 25

c. 3 × 3 × 3 × 3 = 34

d. Express 128 as a product of its prime factors.

Screenshot 2023 08 20 at 06.18.26

128 =  2 × 2 × 2 × 2 × 2 × 2 × 2  =  27

e.  Express 81 as a product of prime factors

Screenshot 2023 08 20 at 06.20.06

81 = 3 × 3 × 3 × 3 =  34

Worked Example 4.1.2:

Evaluate the following;

a. 25
b. 34
c. 55
d. 73

Solution

a. 25 = 2 × 2 × 2 × 2 × 2

= 4 × 4 × 2

= 16 × 2

= 32

b. 34 = 3 × 3 × 3 × 3

= 9 × 9

=  81

c. 55 = 5 × 5 × 5 × 5 × 5

= 25 × 25 × 5 

= 625 × 5 

= 3125

d. 73 = 7 × 7 × 7

=  49 × 7

= 343

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