1.32 To calculate by choosing methods that are appropriate for

Mathematics

Subtraction

Educator section

Memorandum

Leaner section

Content

Activity: to calculate by choosing methods that are appropriate for solving problem [lo 1.8.1]

1. You have already been exposed to a variety of methods for doing subtraction. Now you have to see whether you are able to use your accumulated knowledge meaningfully. Calculate the following, using whatever method you prefer:

1.1 721 435 – 342 668

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1.2 834 206 – 467 937

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1.3 1 000 000 – 386 249

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2. Check your answers by using a pocket calculator.

Time for self-assessment

Let’s see how you are doing! Indicate how you feel about the different methods of subtraction. Colour the faces that reflect your feelings.

Assessment

Learning Outcome 1: The learner will be able to recognise, describe and represent numbers and their relationships, and to count, estimate, calculate and check with competence and confidence in solving problems.

Assessment Standard 1.8: We know this when the learner estimates and calculates by selecting and using operations appropriate to solving problems that involve:

1.8.1: rounding off to the nearest 5, 10, 100 or 1 000.