Starter Write the following as ordinary numbers 9

Starter Write the following as ordinary numbers: 9. 25 × 103 9250 1. 8 × 10 -1 0. 18 7. 248 × 102 724. 8 Write the following in standard form: 0. 00269 2. 69 × 10 -3 518. 3 5. 183 × 102 6. 72 × 100

Starter Round the following to the number of figures specified: 4. 52 (1 dp) 4. 5 34567 (3 sf) 34600 0. 00983 (3 dp) 0. 010 23. 896 (4 sf) 23. 90

Note 12: Percentages Percent mean ‘out of 100’. To convert a percentage to a fraction or decimal, divide by 100. Example: 28% = 28/ 7/ = 100 25 = 0. 28 To convert a fraction or decimal to a percentage, multiply by 100. Example: 0. 45 = 0. 45 × 100 = 45% ⅜ = ⅜ × 100 = 37. 5%

Percentage of a Quantity Convert the percentage to a decimal and multiply by the quantity. Example: 8% of 340 = 0. 08 × 340 = 27. 2 Calculating ‘Original’ Quantities Calculate the original quantity by dividing by the percentage as a decimal. Example: If 30% of a quantity is 54. What is the original quantity. 30% of quantity = 54 0. 3 × quantity = 54 Original quantity = 54 ÷ 0. 3 = 180

Note 13: Percentage One amount as a of another amount Write the information into a fraction and then convert to a percentage. Example: 40 out of 50 pupils love mathematics. What percentage of pupils love mathematics? Percentage = 40/50 × 100% = 80%

Note 14: Calculating Percentage Increase/Decrease To calculate the percentage change: % change = difference in values × 100% original amount

Examples: The number of senior boys at the hostel increases from 60 to 75. What percentage increase is this? % increase = (75 – 60) × 100 = 25% 60 The population of a town decreased from 600 to 540 people. What percentage decrease is this? % decrease = (600 – 540) × 100 = 10% 600

Page 30 Exercise T, U and Worksheet