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To perform mental calculations

Module by: Siyavula Uploaders. E-mail the author

MATHEMATICS

Number Concept

EDUCATOR SECTION

Memorandum

1.1 6

1.2 12

1.3 775

1.4 9

1.5 11

1.6 3 700

1.7 9 rem 3

1.8 6 rem 5

1.9 6 248

1.10 504

1.11 350

1.12 45

1.13 8

1.14 19 000

1.15 1 rem 16

LEANER SECTION

Content

ACTIVITY: To perform mental calculations [LO 1.9.1, LO 1.9.2]

1. By this time you will have realised how important it is to develop a quick mind and do without a pencil and paper. Answer the following questions as quickly and accurately as possible and see whether you are able to improve on the results of your previous mental calculation test:

1.1 54 ÷ 9 = ________________________

1.2 __________________________ x 8 = 96

1.3 5 000 – 4 225 = ___________________

1.4 (7 x ____________________) + 9 = 70

1.5 (9 x 5) - ____________________ = 34

1.6 2 575 + 1 125 = ___________________

1.7 84 ÷ 9 = _________________________

1.8 53 ÷ 8 = _________________________

1.9 Double 3 124: ______________________

1.10 Halve 1 008: _______________________

1.11 250 + 75 + 25 = __________________

1.12 (12 x 12) - ___________________ = 99

1.13 (42 + _____________) x 1 000 = 50 000

1.14 Round off to the nearest 1 000: 19 450 : ___________________

1.15 (9 x 12) ÷ 92 = ________________________

Complete: I have _______________________________ correct!

Table 1
My marks have DROPPED REMAINED THE SAME IMPROVED

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 1.9: We know this when the learner performs mental calculations involving:

1.9.1: addition and subtraction;

1.9.2: multiplication of whole numbers to at least 12 x 12.

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Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

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