PEMDAS

Units & Measurements abbreviation · Math

PEMDAS stands for Parentheses, Exponents, Multiplication/Division, Addition/Subtraction, a math abbreviation.

US mnemonic for the order of operations: parentheses first, then exponents, then multiplication and division from left to right, then addition and subtraction from left to right. Students remember it as "Please Excuse My Dear Aunt Sally".

Example: By PEMDAS, 2 + 3 × 4² = 2 + 3 × 16 = 50.

Usage notes

A common misunderstanding is that multiplication always comes before division and addition before subtraction; each pair actually has equal priority and is evaluated left to right. Viral puzzles such as 6 ÷ 2(1 + 2) exploit ambiguity about implied multiplication, which PEMDAS alone does not settle. Other countries teach the same rules as BODMAS, BEDMAS or BIDMAS.

Related abbreviations

More math abbreviations

• N – Natural numbers
• nCr – Combinations (n choose r)
• nPr – Permutations
• ODE – Ordinary differential equation
• pct – Percent
• PDE – Partial differential equation
• Pf – Proof
• Q – Rational numbers
• QED – Quod erat demonstrandum (which was to be demonstrated)
• R – Real numbers
• Re – Real part
• resp. – Respectively

See all 91 math abbreviations →

Edited by the AbbreviationList.com team. Spotted an error or a missing meaning? Contact us.