DepEd MELC reviewer for Grade 10 Mathematics, Quarter 3. Study the rules, worked formulas, and exam hacks below.
1
Permutations vs Combinations
| Order matters? | Formula | |
|---|---|---|
| Permutation | YES | nPr = n!/(n−r)! |
| Combination | NO | nCr = n!/[r!(n−r)!] |
💡 Exam Hack
Order matters → Permutation (like passwords, rankings). Order does NOT matter → Combination (like teams, groups).
2
Probability of Events
P(A or B) = P(A) + P(B) − P(A and B). For mutually exclusive events, subtract nothing.
P(event) = favorable ÷ total
3
Compound Events
Independent: P(A and B) = P(A)·P(B). Use tree diagrams to list outcomes.
4
Worked Example
How many ways to arrange 3 of 5 books on a shelf?
5P3 = 5!/(5−3)! = 120/2 = 60
Order matters on a shelf, so use permutation.
📌 Quick Recap — Master These
Before your test, make sure you can confidently do each of the following:
- Explain and apply Permutations vs Combinations.
- Explain and apply Probability of Events.
- Explain and apply Compound Events.
- Explain and apply Worked Example.
Re-read any section above where you hesitate, then try the worked example again without looking.