Starter If 4 oranges cost $3.60, how much will nine oranges cost. 1 orange 90 cents 9 oranges $8.10 It takes 5 men 4 hours to chop up some firewood. How long would it take two men? 1 man 20 hours 2 men 10 hours

Starter In a duck egg the ratio of yolk weight to egg-white weight is 3:2. If the egg-white weighs 14g, calculate the weight of the yolk. Yolk = 21g The ratio of weight lifted to their own body weight for a male Olympic-class weightlifter can sometimes exceed 5:2. If a weightlifter weighs 80kg, what weight would he aim to exceed? Aim to lift 200kg

Note 9: Significant Figures The number of significant figures a number has, is the total number of digits that represent it. Example: 3147 (4 sf)

Zeros are significant when they are: inbetween other numbers both at the end of a number and after the decimal point   Examples: 9.703 7.40 (4 sf) (3 sf) Zeros are not significant when they are: at the front of a number at the end of a number with no decimal point   Examples: 0.036 24000 (2 sf) (2 sf)

Note 10: Rounding To round a number to a given number of decimal places/significant figures: Underline the number of decimal place/significant figures required Look at the next digit, if it is less than 5, drop all numbers not underlined 5 or more, then add one to the last digit underlined and drop all other numbers For significant figures, zeros may be needed as place holders

Examples: 3.8194 (2 dp) 4368 (2 sf) 12.895 (2 dp) 0.0546 (1 sf) (3.82)   Examples: 3.8194 (2 dp) 4368 (2 sf) 12.895 (2 dp) 0.0546 (1 sf) (3.82) (4400) (12.90) (0.05)

Note 11: Standard Form Very large and very small numbers are written in standard from. Example: 3.14 × 102

Standard Form Number  Move the decimal point to the right if the power is positive and to the left if the power is negative. Examples: 5.364 × 102 2.46 × 10-1 536.4 0.246 Number Standard Form Move the decimal place to after the first significant figure. Find the value of the power. Examples: 5812 0.019 5.812 × 103 1.9 × 10-2

Page 25 Exercise P Page 27 Exercise R and S