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  • GETIntPhaseMaths display tagshide tags

    This module and collection are included inLens: Siyavula: Mathematics (Gr. 4-6)
    By: Siyavula

    Module Review Status: In Review
    Collection Review Status: In Review

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To perform mental calculations

Module by: Siyavula Uploaders. E-mail the author

MATHEMATICS

Subtraction

EDUCATOR SECTION

Memorandum

1.1 15

1.2 33

1.3 93

1.4 995

1.5 9 997

1.6 99 995

1.7 130

1.8 3 650

1.9 53

1.10 612 1212 size 12{ { { size 8{1} } over { size 8{2} } } } {}

1.11 123

1.12 12

1.13 19

1.14 6

1.15 1212 size 12{ { { size 8{1} } over { size 8{2} } } } {}

Puzzle out old code

1 286 1 335

- 539 - 934

  1. 101

LEANER SECTION

Content

Activity: To perform mental calculations [LO 1.9.1]

1. During the previous activities you have worked with very large numbers. It is equally important to be able to subtract small numbers correctly. Let us see how you will manage the following mental calculations test! Work as quickly and accurately as possible:

1.1 31 – 16 = ______________________________________________________

1.2 52 – 19 =______________________________________________________

1.3 101 – 8 =______________________________________________________

1.4 1 004 – 9 =______________________________________________________

1.5 10 003 – 6 =_____________________________________________________

1.6 100 002 – 7 =____________________________________________________

1.7 240 – 50 – 60 =__________________________________________________

1.8 4 000 – 350 =____________________________________________________

1.9 (530 × 10) ÷ 100 =________________________________________________

1.10 Halve 1 225: ____________________________________________________

1.11 Triple: ________________________________________________________

1.12 (11 × 12) - ______________________________ = 120

1.13 100 – (9 × 9) =___________________________________________________

1.14 (38 -___________________________________) ÷ 4 = 8

1.15 ____________________________________ × 850 = 425

15

Colour in: This time I have done GOOD AVERAGE POOR.

Decipher the code!

Each letter represents a digit. Can you discover the numbers?

Table 1
ROAD   _______________   DEEP _______________
- HIS   _______________   - HER _______________
EWE   _______________   ROD _______________

Do you know that this kind of mathematics is called Alpha-mathematics?

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.

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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.

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