1.29 To perform mental calculations

Mathematics

Subtraction

Educator section

Memorandum

1.1 8 1.9 176

1.2 132 1.10 7

1.3 17 1.11 4

1.4 330 1.12 500

1.5 100 1.13 718

1.6 + 1.14 218 $\frac{1}{2}$

1.7 100 1.15 10 000

1.8 54

Leaner section

Content

Activity: to perform mental calculations [lo 1.9.1, lo 1.9.2]

1. Until now your mental calculation skills have been of cardinal importance to the activities. This is another opportunity to improve these skills further. Let us see how well you perform in the following mental calculation test. Work as quickly and accurately as possible.

1.1 _____________________ × 9 = 72

1.2 _____________________ ÷ 11 = 12

1.3 119 + _____________________ = 136

1.4 _____________________ – 213 = 117

1.5 30 × _____________________ = 3 000

1.6 967 _____________________ 23 = 990

1.7 86 700 ÷ _____________________ = 867

1.8 (4 × 9) + 18 = _____________________

1.9 (7 + 15) x 8 = _____________________

1.10 (42 ÷ _____________________) + 14 = 20

1.11 (5 × _____________________) – 9 = 11

1.12 Halve × _____________________ = 225

1.13 Double: 359: _____________________

1.14 Halve: 437: _____________________

1.15 104 = _____________________

Complete: I have answered ____________________________ correctly!

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.