Number: Fractions · B5 Mathematics

Lesson notes

Learning Objectives

Indicator: B5.1.3.1.5 - Use models to explain the result of multiplying a whole number by a fraction

By the end of the lesson, learners can:

Interpret a multiplication statement like 5 × 2/3 as repeated addition of the fraction (five groups of two-thirds).
Use rectangular fraction bars or number lines to model the product of a whole number and a fraction.
State the product of a whole number and a proper fraction as an improper fraction and convert it to a mixed number.
Use models to multiply a whole number by a mixed fraction, such as 3 × 2 2/3, and express the result correctly.
Explain, with a model, why 4 × 3/5 equals 12/5 and relate this to the repeated addition of 3/5 four times.

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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: B5.1.3.1.5 - Use models to explain the result of multiplying a whole number by a fraction
Suggested placement: Term 2, Week 1 (Week 13 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.74
Curriculum reference: Mathematics Curriculum for Primary Schools (Basic 4-6), 2019, p. 74
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g. 1 Multiplying a whole number by a fraction, e.g. 5 x 2/3 or finding five two-thirds means 2/3 + 2/3 + 2/3 + 2/3 + 2/3 = 10/3 = 3 1/3

Wide colour mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions,... — A wide colour mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions, coloured regions. Visible labels, values, and notation include: E.g. 1 Multiplying a whole number by a fraction, e.g. 5 x; or finding five two-thirds means; =t=+; 2+3+; 3; =$=3}; E.g. 2 To multiply a whole number by a mixed fraction (e.g. 3; ×23) one can muliply the whole number by the; whole number and.

E.g. 2 To multiply a whole number by a mixed fraction (e.g. 3 x 2 2/3) one can multiply the whole number by the whole number and then whole number by the fraction and add the products or change the mixed fraction to improper fraction and multiply; i.e. 3 x 2 2/3 = (3x2) + 3x 2/3 = 6 + 2/3 + 2/3 + 2/3 = 6 6/3 = 8 or 3 x 2 2/3 = 2 2/3 + 2 2/3 + 2 2/3 = 6 2+2+2/3 = 6 6/3 = 8
E.g. 3 To multiply a whole number by a fraction (e.g. 3 x 2 2/3) first change all into common fractions, then multiply the numerators separately and multiply the denominators separately and simplify; i.e. 3 x 2 2/3 = 3/1 x 8/3 = 3x8/1x3 = 24/3 = 8 Every fraction on this page is stacked 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.