Background information on Mental Mathematics
Mental Mathematics forms an integral part of the content area Numbers, Operations and Relationships. The Mental Mathematics programme should be developed systematically over the year and should form part of the daily teaching activities. However, learners should not be asked to do random calculations each day. The focus of each Mental Mathematics exercise should be on one of the following: • To link existing calculating strategies with concepts and skills to be developed in the main part of the next lesson: This is done by starting with number ranges and calculation strategies developed in Grade 4 or during any lessons in Grade 5.
• To revise and reinforce calculating strategies developed in the main part of a previous lesson: This is done by incorporating new topics and calculating strategies into the Mental Mathematics programme. By gradually increasing the number range during the year, a thorough system of revision can be built into the Mental Mathematics programme.
Three aspects of learners’ knowledge should be addressed in the Mental Mathematics programme: • number facts • calculation strategies • number concept.
The following information on these aspects offers some ideas on how to approach Mental Mathematics.
Number facts
This aspect covers the following: • number bonds, which involve addition and subtraction facts for units and multiples of 10, 100 and 1 000;
• times tables, which involve multiplication of whole numbers up to 10 × 10. Number bonds
A number bond is a mental picture of the relationship between a number and the parts that combine to make it. Suppose the number (the whole thing) is 10. The parts (whole numbers) making up 10 can be illustrated as follows:
Subtraction
10 - 0 = 10 10 - 1 = 9 10 - 2 = 8 10 - 3 = 7 10 - 4 = 6 10 - 5 = 5 10 - 6 = 4 10 - 7 = 3 10 - 8 - 2 10 - 9 = 1 10 - 10 = 0
= 1 2 3 4 5 6 7 8 9 10
Number bonds for 10 10
9 8 7 6 5 4 3 2 1 Addition
0 + 10 = 10 1 + 9 = 10 2 + 8 = 10 3 + 7 = 10 4 + 6 = 10 5 + 5 = 10 6 + 4 = 10 7 + 3 = 10 8 + 2 = 10 9 + 1 = 10 10 + 0 = 10
24 Section 3: Teaching and learning Mathematics
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