Exercise 1 Guidelines on how to implement this activity


• Establish whether the learners can answer multiplication facts orally and quickly. Remediate if necessary.


• Revise the columns-method for doing addition and subtraction with whole numbers by doing relevant examples on the board with the participation of the learners. Also do long multiplication.


• Revise the long division method for whole numbers by doing a couple of graded examples, from single-digit-divisors to double-digit divisors. Some learners are likely to have difficulty with this. Let the learners start Exercise 1 in the class and finish it, if necessary, for homework.


• Revise the rounding off and compensating of big whole numbers and the estimation of calculations with whole numbers. Let the learners start Exercise 2 in the class and finish it, if necessary, for homework.


• Revise the properties of whole numbers such as the commutative, associative and distributive properties. Let the learners start Exercise 3 in the class and finish it, if necessary, for homework.


Suggested answers 1.1 1.2 1.3


109 786 + 45 379 = 155 165


239 876 + 345 789 + 654 897 = 1 240 562 324 987 + 90 000 + 87 654 = 502 641


1.4 65 900 – 56 599 = 9 301 1.6 459 653 – 107 996 = 351 657 1.8 8 945 × 489 = 4 374 105


1.10 89 450 × 852 = 76 211 400 2.1


50 232 ÷ 56 = 897 2.3 78 950 ÷ 25 = 3 158


2.5 97 976 ÷ 296 = 331 3.1


345 889 + 231 123 Estimate: 3500 000 + 230 000 ≈ 580 000 350 000 − 345 889 = 4 111 230 000 − 231 123 = −1 123 4 111 + ( −1 123 ) = 2 988 345 889 + 231 123 = 580 000 − 2 988 = 577 012


1.5 108 778 – 99 987 = 8 791 1.7 4 589 × 545 = 2 501 005 1.9 15 852 × 745 = 11 809 740


2.2 34 650 ÷ 22 = 1 575 2.4 52 275 ÷ 123 = 425


3.2 654 098 + 34 876 Estimate: 650 000 + 35 000 ≈ 685 000 650 000 − 654 098 = − 4 098 35 000 − 34 876 = 124 −4 098 + 124 = −3 974


654 098 + 34 876 = 685 000 − (−3 974) = 688 974


Learner’s Book page 21


34 Section 4: Teaching Mathematics


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