Chapter 11 The Study Of Numbers Up To 1000—Ii

Incidentally, mastery of doubling and trebling techniques reduces the essential multiplication tables to those of two, three, seven and ten, those of four, five, six, eight and nine being obtainable from them. However, as has been indicated above, it is not recommended that knowledge of all the tables be neglected. They are all included among the 37 basic products and provide the pupil with essential alternatives to doubling and trebling. Thus, although answers have been restricted for the most part to numbers up to 1000, pupils are now equipped to multiply by 2, 3, 4, 5, 6, 8, 9,10, by 25, 26, 24, 27,23, by 20,30,40, 50, 60, 70, 80, 90 and 100. It remains now to establish methods of multiplying by 7, by 11, and by 12 and then to develop an understanding of multiplying by any two-figure number.

Multiplying By 7 For multiplication by 7, it is necessary to know the seven times table; the alternative informal methods are used: 7 × 58 = 7 × (50 + 8) = 7 × 50 + 7 × 8 = 350 + 56 = 406 = 7 × (60 – 2) = 7 × 60 – 7 × 2 = 420 – 14 = 406

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The Cuisenaire Gattegno method of teaching Mathematics

The Cuisenaire Gattegno method of teaching Mathematics

The Cuisenaire Gattegno method of teaching Mathematics

The Cuisenaire Gattegno method of teaching Mathematics