๐ PEMDAS – The American Version of Order of Operations
PEMDAS is the U.S./North American mnemonic for the same mathematical rule known elsewhere as BODMAS (India/UK/Australia) or BOD (simplified form). Though the names differ, the principle remains universal — a disciplined order to keep our calculations honest and consistent.
๐ค PEMDAS Full Form
| Letter | Meaning | Operations |
|---|---|---|
| P | Parentheses | ( ) → Brackets |
| E | Exponents | x², √x, x³ → Orders |
| MD | Multiplication & Division | × and ÷ → left to right |
| AS | Addition & Subtraction | + and − → left to right |
Key: M and D share equal priority → perform left to right. A and S share equal priority → perform left to right.
๐ PEMDAS vs BODMAS vs BOD
| Mnemonic | Region | Key Difference |
|---|---|---|
| PEMDAS | USA, Canada | Parentheses → Exponents → MD/AS |
| BODMAS | India, UK, Australia | Brackets → Orders → DM/AS |
| BOD | UK (simplified) | Brackets → Orders → D/M → A/S |
All give the same answer — only the words differ!
๐งฎ Worked Examples Using PEMDAS
Example 1: 12 ÷ 3 × 4
Left to right: 12 ÷ 3 = 4 → 4 × 4 = 16
Answer: 16Example 2: (8 + 2) × 3 − 4 ÷ 2
- P: (8 + 2) = 10
- MD: 10 × 3 = 30, 4 ÷ 2 = 2
- AS: 30 − 2 = 28
Example 3: 2 + 6 ÷ 2 × 3 − 1
- MD: 6 ÷ 2 = 3 → 3 × 3 = 9
- AS: 2 + 9 = 11 → 11 − 1 = 10
Example 4: 5 × (4 + 3)² ÷ 7
- P: (4 + 3) = 7
- E: 7² = 49
- MD: 5 × 49 = 245 → 245 ÷ 7 = 35
⚠️ Common PEMDAS Mistakes (and Fixes)
| Mistake | Expression | Wrong Answer | Correct |
|---|---|---|---|
| Doing M before D | 12 ÷ 3 × 4 |
1 | 16 |
| Forgetting left to right | 20 − 3 × 4 + 2 |
6 | 10 |
| Treating PEMDAS as strict order | 10 ÷ 2 × 5 |
1 | 25 |
๐ก PEMDAS Mnemonic Tip
| Letter | Fun Phrase |
|---|---|
| P | Please |
| E | Excuse |
| M | My |
| D | Dear |
| A | Aunt |
| S | Sally |
"Please Excuse My Dear Aunt Sally" — a friendly way to remember the order that keeps math neat and fair.
๐ PEMDAS vs BODMAS: Side-by-Side
| Expression | PEMDAS Steps | BODMAS Steps | Answer |
|---|---|---|---|
10 − 2 × 3 |
M: 2×3=6 → S: 10−6=4 | M: 2×3=6 → S: 10−6=4 | 4 |
18 ÷ 3 × 2 |
18 ÷ 3 = 6 → 6 × 2 = 12 | 18 ÷ 3 = 6 → 6 × 2 = 12 | 12 |
๐ Final Summary Table
| Rule | Region | Order |
|---|---|---|
| PEMDAS | USA | P → E → M/D (←) → A/S (←) |
| BODMAS | India/UK | B → O → D/M (←) → A/S (←) |
| BOD | UK (simple) | B → O → D/M → A/S |
| MAS | Partial (unsafe alone) | Only M → A → S |
Golden Rule: When operations share priority, always go left to right.
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