1.5 To be able to do mental arithmetic

Mathematics

Number concept, addition and subtraction

Educator section

Memorandum

1.1 20

1.2 28

1.3 25

1.4 24

1.5 6

1.6 76

1.7 9

1.8 7

1.9 48

1.10 11

1.11 30

1.12 8

1.13 9

1.14 12

1.15 9

1.16 108

1.17 45

1.18 81

1.19 7

1.20 12

Leaner section

Content

Activity: to be able to do mental arithmetic [lo 1.9]

• In Mathematics it is very important that you must be able to think quickly. Let us see how you COPE! Complete the following mental arithmetic test as quickly and accurately as possible.

1.1 5 × 4 = ___________________

1.2 14 + 9 + 5 = ___________________

1.3 32 − 7 + ___________________

1.4 8 × 3 = ___________________

1.5 7 × ___________________ = 42

1.6 Double 38: ___________________

1.7 ___________________ × 8 = 72

1.8 8 × ___________________ = 56

1.9 4 × 12 = ___________________

1.10 ___________________ × 12 = 132

1.11 126 ÷ 6 + 9 = ___________________

1.12 48 ÷ ___________________ = 6

1.13 12 × ___________________ = 108

1.14 ___________________ × 6 = 72

1.15 54 ÷ 6 = ___________________

1.16 Halve 216: ___________________

1.17 ___________________ ÷ 5 = 9

1.18 ___________________ ÷ 9 = 9

1.19 63 ÷ 9 = ___________________

1.20 144 ÷ 12 = ___________________

Complete: I have __________________________ correct.

DID YOU KNOW?

We use the Hindu-Arabic number system!

The ancient Romans developed their counting system more than 2 000 years ago. Some of their figures look like these:

I ; II ; III ; IV ; V

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.