Chapter 1.2
Combinations
What You'll Learn
Distinguish between permutations and combinations to determine when order matters
Apply the combination formula nCr to calculate selections where order doesn't matter
Solve card problems using combinations for five-card hands and poker scenarios
Interpret 'at least' and 'at most' constraints by identifying relevant cases
Calculate complementary probabilities by subtracting unwanted outcomes from all possibilities
What You'll Practice
1
Forming five-card hands with specific color or face card requirements
2
Committee selection problems with constraints on boys and girls
3
Geometric problems: counting triangles, line segments, and diagonals in polygons
4
At least/at most problems using case addition or complement method
Why This Matters
Combinations help you count choices when order doesn't matteressential for probability, statistics, and real-world decision-making. Whether you're analyzing card games, forming teams, or solving contest math problems, mastering combinations gives you the tools to calculate possibilities efficiently.
Before You Start — Make Sure You Can:
This Unit Includes
17 Video lessons
Practice exercises
Learning resources
Skills
Combinations
nCr Formula
Counting Principles
Complement Method
At Least/At Most
Card Problems
Selection Without Order
OH Curriculum Aligned
