Union and Intersection of Sets: Set Theory Part 3 + Practice

Welcome to Part 3 of our set theory series from ScholarNestHub! Learn how to find the union and intersection of sets step by step, with worked examples, Venn diagrams and practice questions you can try yourself. In this video you will learn: ✅ Union (∪): everything in A or B or both ✅ Intersection (∩): only what is shared by A and B ✅ The empty set and disjoint sets (sets with no overlap) ✅ How to read union and intersection on a Venn diagram ✅ Worked examples: A ∪ B, A ∩ B and sets with no overlap ✅ The counting formula: n(A ∪ B) = n(A) + n(B) − n(A ∩ B) 📝 Practice questions in this video: 1) A = {1, 2, 3} and B = {3, 4, 5}. Find A ∪ B. 2) P = {1, 3, 5} and Q = {5, 7, 9}. Find P ∩ Q. 3) Quiz 1: A = {1, 2, 3} and B = {3, 4}. What is A ∪ B? A) {1, 2, 3, 4} or B) {3} 4) Quiz 2: A = {2, 4, 6} and B = {4, 6, 8}. What is A ∩ B? A) {2, 4, 6, 8} or B) {4, 6} Pause the video, try them, and drop your answers in the comments! ⏮️ New here? Watch Part 1 and Part 2 first so the symbols make sense. ▶️ Next video: Set Theory Part 4, Complement of a Set. 🌐 More free lessons, past questions and e-books: www.scholarnesthub.com 👍 Like, 💬 comment and 🔔 subscribe to ScholarNestHub so you never miss a lesson. This lesson is useful for secondary school students, GCSE, WAEC, NECO and JAMB candidates, and anyone learning set theory. #SetTheory #UnionAndIntersection #Maths