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Starter  What is: 1 1 + 6 2 B) 2 + 3 C) 6 - 2 2 4 3 6 12 3 2 4 3 6 12 3.

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Presentation on theme: "Starter  What is: 1 1 + 6 2 B) 2 + 3 C) 6 - 2 2 4 3 6 12 3 2 4 3 6 12 3."— Presentation transcript:

1 Starter  What is: 1 1 + 6 2 B) 2 + 3 C) 6 - 2 2 4 3 6 12 3 2 4 3 6 12 3

2 Starter: Using a common denominator 1) Write any mixed numbers as improper fractions. 1 3 4 = 7 4 2) Find the lowest common multiple of 4, 9 and 12. The multiples of 12 are:12,24,36... 36 is the lowest common denominator. What is+ 1 9 ? 1 3 4 + 5 12

3 3) Write each fraction over the lowest common denominator. 7 4 = 36 ×9×9 ×9×9 631 9 = 36 ×4×4 ×4×4 45 12 = 36 ×3×3 ×3×3 15 4) Add the fractions together. 36 63 + 36 4 + 15 = 36 63 + 4 + 15 = 36 82 = 2 36 10 = 2 18 5 What is+ 1 9 ? 1 3 4 + 5 12 Using a common denominator

4 Fraction Quantities Objective: How to work with Fractions

5 Class question Please write in your books an example of a fraction or percentage you have seen in the real world??? Discounts in stores ½ off or 50% off VAT??Taxes? Interest Rates?? Money?

6 Finding a fraction of an amount We can see this in a diagram: 2 3 of £18 = £18 ÷ 3 × 2= £12 2 3 of £18? What is

7 Let’s look at this in a diagram again: 7 10 of £20 = £20 ÷ 10 × 7= £14 7 10 of £20? What is Finding a fraction of an amount

8 What is of 9 kg? 4 7 To find of an amount we can multiply by 4 and divide by 7. 4 7 We could also divide by 7 and then multiply by 4. 4 × 9 kg =36 kg 36 kg ÷ 7 = = 36 7 kg 5 1 7 Finding a fraction of an amount

9 5 6 of £24= 1 6 × 5 = £24 ÷ 6 × 5 = £4 × 5 = £20 5 6 of £24? What is Finding a fraction of an amount

10 When we work out a fraction of an amount we multiply by the numerator and divide by the denominator For example, 2 3 of 18 litres = 18 litres ÷ 3 × 2 = 6 litres × 2 = 12 litres Finding a fraction of an amount

11 Examples Find: a) 2 of £ 28 b)3 of 45 sweets c) 1 2 of 15 m 7 5 3 7 5 3A) First, Find 1 of £28: 28 divide by 7 = 4, So, 2 of £ 28 = 2x4=£8 7 7 7 7Or 2x28 Divide by 7 = £ 8 B) First, Find 1 of 45 sweets: 45 divide by 5 = 9 5 So, 3 of 45 sweets = 3x9 = 27 sweets So, 3 of 45 sweets = 3x9 = 27 sweets 5Or 3x45 Divide by 5= 27 sweets

12 Exercises 2B page 20  Questions 1-2


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