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JSS1: MATHEMATICS - 2ND TERM

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  1. Algebraic Processes | Week 1
    4 Topics
    |
    1 Quiz
  2. Simplification of Algebraic Expressions | Week 2
    4 Topics
    |
    1 Quiz
  3. Simplification of Algebraic Expressions 2 (Use of Brackets) | Week 3
    4 Topics
    |
    1 Quiz
  4. Simple Equations | Week 4
    1 Topic
    |
    1 Quiz
  5. Simple Equations II | Week 5
    3 Topics
    |
    1 Quiz
  6. Plane Shapes I | Week 6
    5 Topics
    |
    2 Quizzes
  7. Plane Shapes II | Week 7
    7 Topics
    |
    1 Quiz
  8. Plane Shapes III | Week 8
    7 Topics
    |
    1 Quiz
  9. Decimal and Percentages I | Week 9
    2 Topics
    |
    1 Quiz
  10. Decimal and Percentages | Week 10
    3 Topics
    |
    1 Quiz



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Substituting Numbers:

The value of an expression such as x + 8  can be found by replacing x with a given number. This is called substitution. For example:  

For the expression x + 8 

If  x = 8,  then  8 + 8  = 16

If x = 10, then 10 + 8  =  18

Example 1

Find the value of each of the following mentally when  x = 3

i. \( \scriptsize x + 10 \\ \rightarrow \scriptsize 3 + 10 \\ = \scriptsize 13 \)

ii. \( \scriptsize x\: – \: 1 \\ \rightarrow \scriptsize 3\: – \: 1 \\ = \scriptsize 2 \)

iii. \( \scriptsize x \: \times \: 8 \\ \rightarrow \scriptsize 3 \: \times \: 8 \\ = \scriptsize 24 \)

iv. \( \scriptsize x \: \div \: 9 \\ \rightarrow \scriptsize 3 \: \div\: 9 \\ = \frac{3}{9} \\ = \frac{1}{3} \)

v. \( \scriptsize x \: \times \: 3 + 1 \\ \rightarrow \scriptsize 3 \: \times \: 3 + 1 \\ = \scriptsize 10 \)

Example 2

Find the value of each of the following mentally when  y = 20

i. \( \scriptsize y + y + 2 \\ \rightarrow \scriptsize 20 + 20 + 2 \\ = \scriptsize 42 \)

ii. \( \scriptsize (y \: – \: y ) \: + \: 5 \\ \rightarrow \scriptsize (20 \: – \: 20) \: + \: 5 \\ \scriptsize = 0 \: + \: 5 \\ \scriptsize = 5 \)

iii. \( \scriptsize (y \: – \: 10) \: \times \: 8 \\ \rightarrow \scriptsize (20 \: – \: 10) \: \times \: 8 \\ = \scriptsize 10 \: \times \: 8 \\ \scriptsize = 80 \)

iv. \( \scriptsize y \: \div \: y \: + \: 25 \\ \rightarrow \scriptsize 20 \: \div \: 20 \: + \: 25 \\ = \scriptsize 1 + 25 \\= \scriptsize 26 \)

v. \( \scriptsize y \: – \: y \: + \: 8 \\ \rightarrow \scriptsize 20 \: – \: 20 \: + \: 8 \\ \scriptsize = 20 \: – \: 28 \\ \scriptsize = \; – 8 \)

Remember BODMAS.

B = Brackets \( \scriptsize \left( \right)\)

O = Orders \( \scriptsize x^2 \: \: \sqrt{x} \)

D = Division \( \scriptsize \div \)

M = Multiplication \( \scriptsize \times \)

A = Addition \( \scriptsize + \)

S = Subtraction \( \scriptsize – \)

For question v. we solved 20 + 8 first which is equal to 28. We then solved the subtraction 20 – 28 = -8. For question ii. we solved the bracket first (20 – 20) = 0

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