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This collection is included inLens: Siyavula: Mathematics (Gr. 4-6)
By: Siyavula

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# To perform mental calculations

Module by: Siyavula Uploaders. E-mail the author

## Memorandum

INTRODUCTION

The learning programme for grade six consists of five modules:

1. Number concept, Addition and Subtraction

2. Multiplication and Division

3. Fractions and Decimal fractions

4. Measurement and Time

5. Geometry; Data handling and Probability

• It is important that educators complete the modules in the above sequence, as the learners will require the knowledge and skills acquired through a previous module to be able to do the work in any subsequent module.

COMMON AND DECIMAL FRACTIONS (LO 1; 2 AND 5)

LEARNING UNIT 1 FOCUSES ON COMMON FRACTIONS

• This module continues the work dealt with in grade 5. Addition and subtraction of fractions are extended and calculation of a fraction of a particular amount is revised.
• Check whether the learners know the correct terminology and are able to use the correct strategies for doing the above correctly.
• Critical outcome 5 (Communicating effectively by using visual, symbolic and /or language skills in a variety of ways) is addressed.
• It should be possible to work through the module in 3 weeks.
• ** Activity 17 is designed as a portfolio task. It is a very simple task, but learners should do it neatly and accurately. They must be informed in advance of how the educator will be assessing the work.
• LEARNING UNIT 2 FOCUSES ON DECIMAL FRACTIONS
• This module extends the work that was done in grade 5. Learners should be able to do rounding of decimal fractions to the nearest tenth, hundredth and thousandth. Emphasise the use of the correct method (vertical) for addition and subtraction. Also spend sufficient time on the multiplication and division of decimal fractions.
• As learners usually have difficulty with the latter, you could allow 3 to 4 weeks for this section of the work.
• ** Activity 19 is a task for the portfolio. The assignment is fairly simple, but learners should complete it neatly and accurately. They must be informed in advance of how the educator will be assessing the work.

1.1 70

1.2 983

1.3 438

1.4 354 1212 size 12{ { { size 8{1} } over { size 8{2} } } } {}

1.5 9

1.6 132

1.7 8

1.8 5656 size 12{ { { size 8{5} } over { size 8{6} } } } {}

1.9 5656 size 12{ { { size 8{5} } over { size 8{6} } } } {}

1.10 27

1.11 29

1.12 7878 size 12{ { { size 8{7} } over { size 8{8} } } } {}

1.13 1 1818 size 12{ { { size 8{1} } over { size 8{8} } } } {}

1.14 3434 size 12{ { { size 8{3} } over { size 8{4} } } } {}

1.15 10 000

## Content

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

Complete the following mental calculation test as quickly and accurately as possible and try to improve on your previous performance!

 1.1 26 + 19 + 25 = ..............… 1.6. 12 x 11 = ..........….......... 1.2. 1 004 – 21 = ................…. 1.7 56 ÷ ..............… = 7 1.3. Double 219: ..............… 1.8 Simplify 15211521 size 12{ { {"15"} over {"21"} } } {}: 1.4. Halve 709: ...........…....... 1.9 Simplify 25302530 size 12{ { {"25"} over {"30"} } } {}: 1.5. 45 ÷ ..............… = 5 ?1.10 3939 size 12{ { {3} over {9} } } {} = 99 size 12{ { {9} over {} } } {} ?1.11 358358 size 12{3 { {5} over {8} } } {} = 88 size 12{ { {} over {8} } } {} 1.14 112112 size 12{1 { {1} over {2} } } {} – 3434 size 12{ { {3} over {4} } } {} = 2 – 7878 size 12{ { {7} over {8} } } {} = 1.12 1212 size 12{ { {1} over {2} } } {} + 3838 size 12{ { {3} over {8} } } {} = 1.15 104 = 1.13 2 – 7878 size 12{ { {7} over {8} } } {} =

I have done………………………………………………………………………. correctly!

## 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:

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

## Content actions

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PDF | EPUB (?)

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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?

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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