Teaching Pack – Venn diagrams Lesson 1 – Interpreting Venn diagrams Cambridge IGCSE™ Mathematics 0580 Version 1.0 Lesson objectives • Understand how to use Venn diagrams to classify objects and sort data. • Interpret Venn diagrams. Try this! Where would you put each shape? Why? a) b) c) Sorting objects and data Sort these people into those wearing a tie and those with black hair. Wearing a tie Black hair Notations n The number of elements in one set. E Universal Set is the set that contains everything we started with. E Wearing a Tie Black Hair n (wearing a tie) = 4 Universal set Rather than drawing the pictures, we can just write the number of people in each section as follows: Wearing a Tie Black Hair E Wearing a Tie 2 Black Hair 2 3 2 We can also say n(Wearing a Tie) = 2 + 2 = 4 n(Black Hair) = 2 + 3 = 5 Try this! In a survey, 25 people were asked their age and if they owned an iPhone. The results were put into a Venn diagram. E • How many people were under 18? • How many people owned an iPhone? 13 10 2 Under 18 5 8 Own an iPhone 7 • How many people did not own an iPhone? 12 • How many under 18s owned an iPhone? 5 • How can you describe the people represented by 10? Over 18 and does not own an iPhone. Try this! The village holds an annual Fun Run. Contestants are either classified as under the age of 13 or adults. Every contestant must enter for either the 3 kilometre run or the 10 kilometre run. This information is shown in the Venn diagram below: E 10 • • 23 7 50 • • Under 13 Entered for 10 km How many people entered the fun runs? 90 How many people entered the 10 km run? 57 How many under 13s did the 10 km run? 7 How many adults did the 3 km run? 10 Try this! A class of students were classified using the Venn diagram below. E 6 10 Male 12 8 Left handed 12 males are left handed. There are 8 females. 10 people are right handed. There are 36 people in the class. Try this! The same class of 36 students were asked separately: a) If they could swim b) If they could ride a bike 25 said they could swim 18 said they could ride a bike, 4 said they could do neither. E Can ride a bike 4 Is this possible? 14 11 7 Can swim