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% % Percentages Understanding percentage as the number of parts in every 100 % Chris Clements % <date> Learning Objective: LO: I know that 'per cent' means parts in every 100 . Percentage (%) The word ‘percentage’ originates from a Latin word meaning by the hundred. Can you think of any words that begin with ‘cent’? centipede century cents What do you notice? Look at the square. 100% of is shaded purple. Can you see it is made up of 100 equal parts? What percentage of the shape is shaded purple now? What percentage of the shape is shaded white? 90% + 10% = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded purple? 50% + 50% = 100% What fraction is equivalent to 50%? What percentage of the shape is shaded white? What percentage of the shape is shaded purple? 25% + 75% = 100% What fraction is equivalent to 25%? What fraction is equivalent to 75%? Now the square is made up of 10 different colours. What percentage of each colour is there? What fraction is 10% equivalent to? 10% x 10 = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded purple? 37% + 63% = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded purple? 61% + 39% = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded purple? 88% + 12% = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded red? What percentage of the shape is shaded purple? 30% + 50% + 20% = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded red? What percentage of the shape is shaded purple? 35% + 35% + 30% = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded red? What percentage of the shape is shaded purple? 22% + 56% + 22% = 100% What percentage of the shape is shaded white? What percentage of the shape is shaded red? What percentage of the shape is shaded purple? 50% + 46% + 4% = 100% What do you notice about this shape? To work out the percentage we first need to find what % each part is worth? To do this we need to divide a 100 by the number of parts. 100% ÷ 20 = 5% Each part = 5% What percentage of the shape is shaded purple? 5% x 13 = 65% What percentage of the shape is shaded white? 5% x 7 = 35% 65% + 35% = 100% Steps to success 1) Remember one whole is equal to 100% 2) Find the percentage of parts shaded 3) Check to see if the unshaded part + the shaded part = 100 For shapes not divided into 100 parts. Use this formula to work out what percentage each part is worth; 100 ÷ No. of parts in a shape = % of each part 100 ÷ 2 (no. of parts) = 50% Each part of this shape = 50% So 50% is shaded blue 50% is shaded white Plenary ½ 25% ¼ 50% 10% 75% 1 10 ¾ Can you match the percentages to the same value fraction? 34% 46% 58% 91% 19% 23% Which of these fractions show more than ½?