B5 Mathematics · Term 1 Week 12: Number: Fractions

Lesson notes

Learning Objectives

Indicator: B5.1.3.1.3 - Use the concept of equivalent fractions in changing fractions to the same denominator for addition and subtraction of like fractions (one denominator being a multiple of the other)

By the end of the lesson, learners can:

Identify when one denominator is a multiple of another denominator in a pair of fractions.
Find the Lowest Common Denominator (LCD) of two fractions where one denominator is a multiple of the other.
Convert fractions to equivalent fractions with the same denominator using multiplication.
Add and subtract fractions with different denominators by first rewriting them as equivalent fractions with the LCD.
Simplify sums and differences into their lowest terms where possible.

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Curriculum details

Strand: Number (Strand 1)
Sub-strand: Number: Fractions (1.3)
Content standard: B5.1.3.1 - Demonstrate understanding of strategies for comparing, adding, subtracting and multiplying fractions
Indicator: B5.1.3.1.3 - Use the concept of equivalent fractions in changing fractions to the same denominator for addition and subtraction of like fractions (one denominator being a multiple of the other)
Suggested placement: Term 1, Week 12 (Week 12 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.
Source document note: The official curriculum document has a fault in this entry, so the curriculum text above is transcribed exactly as printed:

exemplars - p.73
Curriculum reference: Mathematics Curriculum for Primary Schools (Basic 4-6), 2019, p. 73
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g. 1 To add or subtract the fractions, 1/3 and 2/6, we need find the Lowest Common Denominator (LCD) and use this to express the equivalent fractions. The LCD is 6 and the equivalent fractions are 2/6 and 2/6; their sum is 2/6 + 2/6 is 2+2/6, which is, 4/6 = 2/3 (i.e. its simplest form)
E.g. 2 To add or subtract the fractions, 2/3 and 2/5, we need find the Lowest Common Denominator (LCD) and use this to express the equivalent fractions. The LCD is 15 and the equivalent fractions are 10/15 and 6/15; their difference is 10/15 - 6/15 = 10-6/15 = 4/15 Every fraction on this page is set as stacked numerator over denominator and its parts interleave with the sentence in the text layer; they are written here inline. A reviewer should check each fraction against the page.