1.21 To use techniques to do calculations

Mathematics

Number concept, addition and subtraction

Addition

Educator section

Memorandum

2. 1.3 1 236

3.1 10 876 + 23 982 M+

43 567 + 21 309 M+

RM = 130 254

3.2 42 861 + 13 579 M+

49 478 + 24 336 M+

RM = 130 254

4. 2 x 17.99 M+

3 x 14.99 M+

2 x 6.98 M+

2 x 16.99 M+

RM = 128.89

Leaner section

Content

Activity: to use techniques to do calculations [lo 1.10]

DID YOU KNOW?

You can use the memory keys of your pocket calculator to do calculations containing more than one operation, correctly!

1. Look for the following keys on your pocket calculator: M+ ; MR or RCM

2. Look carefully at the example:

(168 + 423) + (256 + 389)

2.1 Press 168 + 423 = M+

2.2 Then press 256 + 389 = M+

2.3 Then press MR or RCM

What is the answer?

TAKE NOTE:

The M+-key makes it possible for the calculator to memorise or store the answer.

The MR (Memory Recall) or RCM (ReCall Memory) key is used when you want to recall all the memorised answers.

3. Use your pocket calculator’s memory to calculate:

3.1 (10 876 + 23 982) + (43 567 + 21 309)

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3.2 (42 861 + 13 579) + (49 478 + 24 336)

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4. Look at the till slip of the Stay Healthy Chemist. Use the memory of your pocket calculator to calculate the total cost of your purchases.

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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 1.10: We know this when the learner uses a range of techniques to perform written and mental calculations with whole numbers;

1.10.1 adding and subtracting in columns;

1.10.2 building up and breaking down numbers;

1.10.3 rounding off and compensating;

1.10.5 using a calculator.