JHS1 Mathematics · Term 2 Week 5: Algebraic Expressions

Lesson notes

Learning Objectives

Indicator: B7.2.2.1.1 - Create simple algebraic expressions using simple logic to translate a set of instructions into an algebraic expression.

By the end of the lesson, learners can:

Translate simple verbal mathematical phrases (such as “10 more than a number” or “3 times a number”) into algebraic expressions using a letter to represent the unknown number.
Form algebraic expressions from two-step multi-operation statements, such as “2 more than 5 times a number x.”
Create algebraic expressions from real-life situations involving ages, sharing money, profit, area and perimeter.
Explain in their own words how the letter x (or any variable) stands for an unknown value, and defend their choice of operations when translating a given statement.

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Curriculum details

Strand: Algebra (Strand 2)
Sub-strand: Algebraic Expressions (2.2)
Content standard: B7.2.2.1 - Simplify algebraic expressions involving the four basic operations and substituting values to evaluate algebraic expressions.
Indicator: B7.2.2.1.1 - Create simple algebraic expressions using simple logic to translate a set of instructions into an algebraic expression.
Suggested placement: Term 2, Week 5 (Week 17 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Mathematics, Common Core Programme (JHS1-JHS3), 2023, p. 35
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g.1 Form algebraic expressions for given mathematical statements. If x represents an unknown number, then
i. 10 more than a number x→ x + 10
ii. 5 less than a certain number x → x - 5
iii. 3 times a number x → 3x
iv. Half of a certain number x → 1 x or x 2 2
v. 2 more than 5 times a certain number x → 5x + 2
vi. When 8 times a certain number x is subtracted from 5 and the result is multiplied by 2→ 2(5 - 8x)
E.g.2 Form algebraic expressions from real life situations.
i. Afrako is 3 years older than Maako. If Maako is now x years old, what is Afrako's age?
ii. Agbolosu and Tetteh were given GH₵400.00 to share. Tetteh had GH₵35.00 more than Agbolosu. If Agbolosu's share is x, write an expression for Tetteh's share.
iii. Find the profit a woman makes if she buys a basket of oranges for x cedi sand sells it for y cedes.
iv. Find the area of a rectangle which is t metres long and q metres wide.
v. Find the perimeter of a rectangle which is x metres long and y metres wide.