Unknowns, Expressions and… · B4 Mathematics

Lesson notes

Learning Objectives

Indicator: B4.2.2.2.6 - Represent and solve a given addition or subtraction problem involving a “part-part-whole” or comparison context, using a symbol to represent the unknown

By the end of the lesson, learners can:

identify the unknown quantity in a word problem involving part-part-whole or comparison situations and choose a symbol (such as a box, letter, or question mark) to represent it
represent a given addition or subtraction word problem as a one-step equation with the unknown on either side
solve the resulting equation by applying the inverse operation (addition to undo subtraction, or subtraction to undo addition)
write a complete answer sentence for each solved problem, stating the value of the unknown in the context of the story
justify their solution by substituting the value back into the equation and checking that both sides balance

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Curriculum details

Strand: Algebra (Strand 2)
Sub-strand: Unknowns, Expressions and Equations (2.2)
Content standard: B4.2.2.2 - Solve one-step equations involving a symbol to represent an unknown number
Indicator: B4.2.2.2.6 - Represent and solve a given addition or subtraction problem involving a "part- part-whole" or comparison context, using a symbol to represent the unknown
Suggested placement: Term 3, Week 1 (Week 25 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 Curriculum for Primary Schools (Basic 4-6), 2019, p. 35
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g. 1. Ask students to represent and solve these problems: (i) Eunice is Anita's older sister. The difference between their ages is 21 years. Anita is 37 How old is Eunice? (ii) Ms. Akoto allowed 7 students to go to the washroom. There were 15 students left in the room. How many students are in the class?