Number Operations (Addition… · B3 Mathematics

Lesson notes

Learning Objectives

Indicator: B3.1.2.4.3 - Develop and explain estimation strategies to estimate the solution for a given word problem involving addition or subtraction sums up to 1000

By the end of the lesson, learners can:

Round numbers to the nearest hundred to create simpler numbers for estimation.
Estimate the sum of two numbers up to 1000 by adding the rounded numbers.
Estimate the difference between two numbers up to 1000 by subtracting the rounded numbers.
Explain in their own words why an estimate is close to, but not exactly the same as, the exact answer.
Solve word problems set in everyday situations by first estimating the answer and then justifying their estimate.

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Curriculum details

Strand: Number (Strand 1)
Sub-strand: Number Operations (Addition, Subtraction, Multiplication and Division) (1.2)
Content standard: B3.1.2.4 - Develop and apply personal and standard strategies for adding and subtracting within 1000
Indicator: B3.1.2.4.3 - Develop and explain estimation strategies to estimate the solution for a given word problem involving addition or subtraction sums up to 1000
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.
Curriculum reference: Mathematics Curriculum for Primary Schools (Basic 1-3), 2019, p. 53
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g. 1. To estimate the sum of 430 + 561, use 400 + 500. The sum must be close to 900; to estimate the different of 660 and 430, use 600 and 400 or 700 and 400. The difference must be close to 200 or 300.)