The theta symbol, θ (lowercase) and Θ (capital), is the Greek letter that means “the angle.” In trigonometry, sin θ and cos θ use it the way algebra uses x — as the stand-in for an unknown angle. It also shows up in brain waves, options trading, and statistics. It isn’t on an English keyboard,…
Copy the omega symbol Ω ω or type it: Alt+937 on Windows, Option+z on Mac. Plus Ω the letter vs the ohm sign, alpha and omega, ohms in electronics, and omega vs omicron.
Copy the sigma symbol Σ σ ς or type it: Alt+931 on Windows, 03A3 then Alt+X in Word. Plus the two lowercase sigmas, what σ means in stats, Six Sigma, and sigma slang.
Copy the delta symbol Δ δ ∆ or type it: Alt+916 on Windows, Option+j on Mac. Plus Δ the letter vs ∆ the change operator, why delta means change, and river deltas.
Copy the cubed symbol ³ or type it: Alt+0179 on Windows, 00B3 then Alt+X in Word. Plus why it is called cubed, cubic units, why cm³ = cc = mL, and how to cube in code.
Copy the summation symbol ∑ or type it: Alt+8721 on Windows, Option+w on Mac. Plus ∑ the operator vs Σ the Greek letter, how to read a summation, ∑ in code, and ∑ vs ∏.
Copy the approximately-equal symbol ≈ or type it: Alt+8776 on Windows, Option+x on Mac. Plus ≈ vs ~ vs ≅, comparing floats with a tolerance in code, and congruent vs similar.
Copy the not-equal symbol ≠ or type it: Alt+8800 on Windows, Option+= on Mac. Plus why code uses != or not ≠, the Excel operator, and the slash-means-not family.
Copy the division symbol ÷ or type it: Alt+0247 on Windows, Option+/ on Mac. Plus the obelus origin, ÷ vs the colon in Europe, why ÷ starts viral math arguments, and using / in code.
Copy the multiplication symbol × or type it: Alt+0215 on Windows, 00D7 then Alt+X in Word. Plus why × is not the letter x, the dot vs asterisk, why algebra drops it, and × as by.