1.21 To perform mental calculations

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!

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.