Table of mathematical symbols by introduction date

Àwọn tábìlì yìí ṣe àkójọ ọ̀pọ̀lọpọ̀ àwọn ìdánimọ̀ tí a ma ń sábà lọ́ ní ìmọ̀ ìṣirò, tí a tò wọ́n gẹ́gẹ́ bí àkókò tí ṣàfihàn rẹ̀.

Àmi ìdánimọ̀	Orúkọ	Ìgbà àkọ́kọ́ tí wọ́n lòó	Àkọ̀wé tí ó kọ́kọ́ lòó
+	plus sign	ca. 1360 (abbreviation for Latin et resembling the plus sign)	Nicole Oresme
−	minus sign	1489	Johannes Widmann
√	radical symbol (for square root)	1525	Christoff Rudolff
(…)	parentheses (for precedence grouping)	1544 (in handwritten notes)	Michael Stifel
		1556	Niccolò Tartaglia
=	equals sign	1557	Robert Recorde
×	multiplication sign	1618	William Oughtred
±	plus-minus sign	1628
∷	proportion sign
n√	radical symbol (for nth root)	1629	Albert Girard
< >	strict inequality signs (less-than sign and greater-than sign)	1631	Thomas Harriot
xy	superscript notation (for exponentiation)	1636 (using Roman numerals as superscripts)	James Hume
		1637 (in the modern form)	René Descartes
√ ̅	radical symbol (for square root)	1637 (with the vinculum above the radicand)	René Descartes
%	percent sign	ca. 1650	unknown
÷	division sign (a.k.a. obelus)	1659	Johann Rahn
∞	infinity sign	1655	John Wallis
≤ ≥	unstrict inequality signs (less-than or equals to sign and greater-than or equals to sign)	1670 (with the horizontal bar over the inequality sign, rather than below it)
		1734 (with double horizontal bar below the inequality sign)	Pierre Bouguer
d	differential sign	1675	Gottfried Leibniz
∫	integral sign
:	colon (for division)	1684 (deriving from use of colon to denote fractions, dating back to 1633)
·	middle dot (for multiplication)	1698 (perhaps deriving from a much earlier use of middle dot to separate juxtaposed numbers)
⁄	division slash (a.k.a. solidus)	1718 (deriving from horizontal fraction bar, invented by Arabs in the 12th century)	Thomas Twining
≠	inequality sign (not equal to)	unknown	Leonhard Euler
∑	summation symbol	1755
∝	proportionality sign	1768	William Emerson
∂	partial differential sign (a.k.a. curly d or Jacobi's delta)	1770	Marquis de Condorcet
x′	prime symbol (for derivative)		Joseph Louis Lagrange
≡	identity sign (for congruence relation)	1801 (first appearance in print; used previously in personal writings of Gauss)	Carl Friedrich Gauss
[x]	integral part (a.k.a. floor)	1808
∏	product symbol	1812
!	factorial	1808	Christian Kramp
⊂ ⊃	set inclusion signs (subset of, superset of)	1817	Joseph Gergonne
		1890	Ernst Schröder
|…|	absolute value notation	1841	Karl Weierstrass
	determinant of a matrix		Arthur Cayley
‖…‖	matrices notation	1843
∇	nabla symbol (for vector differential)	1846 (previously used by Hamilton as a general-purpose operator sign)	William Rowan Hamilton
∩ ∪	intersection union	1888	Giuseppe Peano
∈	membership sign (is an element of)	1894
∃	existential quantifier (there exists)	1897
ℵ	aleph symbol (for transfinite cardinal numbers)	1893	Georg Cantor
{…}	braces, a.k.a. curly brackets (for set notation)	1895
ℕ	Blackboard bold capital N (for natural numbers set)		Giuseppe Peano
·	middle dot (for dot product)	1902	J. Willard Gibbs?
×	multiplication sign (for cross product)
∨	logical disjunction (a.k.a. OR)	1906	Bertrand Russell
(…)	matrices notation	1909	Gerhard Kowalewski
[…]		1913	Cuthbert Edmund Cullis
∮	contour integral sign	1917	Arnold Sommerfeld
ℤ	Blackboard bold capital Z (for integer numbers set)	1930	Edmund Landau
ℚ	Blackboard bold capital Q (for rational numbers set)
∀	universal quantifier (for all)	1935	Gerhard Gentzen
∅	empty set sign	1939	André Weil / Nicolas Bourbaki
ℂ	Blackboard bold capital C (for complex numbers set)	1939	Nathan Jacobson
→	arrow (for function notation)	1936 (to denote images of specific elements)	Øystein Ore
		1940 (in the present form of f: X → Y)	Witold Hurewicz
∎	end of proof sign (a.k.a. tombstone)	1950	Paul Halmos
⌊x⌋ ⌈x⌉	greatest integer ≤ x (a.k.a. floor) smallest integer ≥ x (a.k.a. ceiling)	1962	Kenneth E. Iverson