# OpenStax_CNX

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• GETIntPhaseMaths

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By: Siyavula

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# To perform mental calculations

Module by: Siyavula Uploaders. E-mail the author

## Memorandum

Multiplier

### Multiplicant

Factors

Multiples

1 x 3 786; 2 x 1 893; 6 x 631; 631 x 6

BRAIN TEASERS

3 786 3 786 x 1; 1 893 x 2

3 x 1 262; 1 262 x 3

1 x 8 742; 8 742 x 1; 6 x 1 457; 1 457 x 6

8 742 2 x 4 371; 4 371 x 2

3 x 2 914; 2 914 x 3

## Content

### Activity:To perform mental calculations [LO 1.9.2]

1. How well do you know your 12 × table? Count in 12’s and colour each answer in green.

If you do this correctly you will find the answer to the following:

Multiplication is actually repeated _________________________________________

 12 14 34 41 68 70 82 100 109 124 131 142 150 197 A W V F H O B G X H B E T S 22 24 36 46 64 73 96 110 112 126 135 146 151 180 B D D T I U N A Z R D O R E 30 26 32 48 62 71 84 115 119 120 137 144 154 168 M Y R I E J O I C T K E A V 41 28 40 50 60 72 101 117 121 129 132 148 156 165 S K T B T I Y D H S W F L F
• Can you find any more multiples of 12? Colour them in blue.

What word does your answer spell? _______________________________________

2. LET US REVISE!

Fill in the missing answer:

In 24 x 17 = 408, we call:

17 the________________________________________________________________

408 the_______________________________________________________________

24 the________________________________________________________________

24 and 17 ______________________________________________________ of 408

408 a ___________________________________________________________ of 17

## 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.

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