List of mathematical symbols

The list below has some of the most common symbols in mathematics. However, these symbols can have other meanings in different contexts other than math.

+ Symbol  Name  Read as Meaning Example(s)= Equal is equal to If x=y, x and y represent the same value or thing. 5(2)=10≡ Definition is defined as If x≡y, x is defined as another name of y ϕ≡(√5+1)/2≈1.618≈ Approximately equal is approximately equal to If x≈y, x and y are almost equal. √2≈1.41≠ Inequation does not equal, is not equal to If x≠y, x and y do not represent the same value or thing. 1+1≠3<Strict inequality is strictly less than If x<y, x is less than y. 4<5> is strictly greater than If x>y, x is greater than y. 3>2≪ is much less than If x≪y, x is much less than y. 0.001≪999999999≫ is much greater than If x≫y, x is much greater than y. 999999999≫0.001≤Inequality is less than If x≤y, x is less than or equal to y. 5≤6 and 5≤5≥ is greater than If x≥y, x is greater than or equal to y. 2≥1 and 2≥2∝ Proportionality is proportional to If x∝y, then y=kx for some constant k. If y=4x then y∝x and x∝y+ Addition plus x+y is the sum of x and y. 2+3=5- Subtraction minus x-y is the subtraction of y from x 5-3=2× or · or *Multiplicationtimes
or multiplied by x×y or x·y  is the multiplication of x by y 4×5=20 or 4·5=20 ÷ or / or :Divisiondivided byx÷y or x/y is the division of x by y 20÷4=5 or 20/4=5± Plus-minus plus or minus x±y means both x+y and x-y 1±2 represents both 3 and -1 ∓ Minus-plus minus or plus 4±(3∓5) means both 4+(3-5) and 4-(3+5) 6∓(1±3)=2 or 4√ Square root square root √x is a nonnegative number whose square is x. √4=2∑ Summation sum over … from … to … of, beta   is the same as x1+x2+x3+...+xn ∏ Product product over … from … to … of  is the same as x1×x2×x3×....×xn =1×2×3×4×5=120! Factorial factorial n! is the product 1×2×3...×n 5!=1×2×3×4×5=120⇒ Material implication implies A⇒B means that if A is true, B must also be true, but if A is false, B is unknown. x=3⇒x2=9, but x2=9⇒x=3 is false, because x could also be -3.⇔ Material equivalence if and only if If A is true, B is true and if A is false, B is false. x=y+1⇔x-1=y|…| Absolute value absolute value of |x| is the distance along the real line (or across the complex plane) between x and zero. |x|=x and |-x|=x || Parallel is parallel to If A||B then line A will never touch line B, thus both lines are rotated in the same angle.x||(x+1)⊥ Perpendicular is perpendicular to If A⊥B then line A is touching line B in a 90 degrees angle.x⊥y≅ Congruence is congruent to If A≅B then shape A and B same shape and size, or A has the same shape and size as the mirror image of B.If two triangles, △ABC and △DEF, are congruent, it can be denoted as △ABC≅△DEFφ Golden ratio golden ratio The golden ratio is an irrational number equal to (1+√5)÷2 or approximately 1.6180339887.φ ≈ 1.6180339887∞ Infinity infinity ∞ is a symbol used to represent unending amounts.∞ + x = ∞∈Set membership is an element of a∈S means that a is an element of the set S 3.5∈ℝ, 1∈ℕ, 1+i∈ℂ∉ is not an element of a∉S means that a is not an element of the set S 2.1∉ℕ, 1+i∉ℝ{,} Set brackets the set of {a,b,c} is the set consisting of a, b, and c S = { a, b, c }ℕ Natural numbers N ℕ denotes the set of natural numbers1∈ℕ, 2∈ℕ, 100∈ℕℤ Integers Z ℤ denotes the set of integers -1∈ℤ, 0∈ℤ, 30∈ℤℚ Rational numbers Q ℚ denotes the set of rational numbers 8.323∈ℚ, 7∈ℚ, π∉ℚℝ Real numbers R ℝ denotes the set of real numbers π∈ℝ, 7∈ℝ, √(-1)∉ℝℂ Complex numbers C ℂ denotes the set of complex numbers √(-1)∈ℂx̄ Mean bar, overbar x̄ is the mean (average) of xi if x={1,2,3} then x̄=2x̄ Complex conjugate the complex conjugate of x If x=a ± bi, then x̄=a ∓ bi where i=√(-1) x=-4 + 5.3i, x̄=-4 - 5.3i[+|-]Situational plus minusEither plus or minus depending on the situation.If y=[+|-]x then x is either positive or negative depending on the situation.y=[+|-]x y equals either +x or -x depending on the scenario.π                  Irrational numbers       pi∴ThereforeSoWhen a sum of information is related to the next1+1=2 ∴ 2-1=1

 Related page 

 Mathematical constant

 Other websites 

 Mathematical Symbols — Math Vault
 Math Symbols List —

Symbols
Category:Symbols
Category:Mathematical notation