symbol  name  keyboard 

√ 
square root 
ALT251, ⌥ v 
∛ ∜ 
cube root & quad root 

÷ 
obelus (ahbelus), 6÷2=3 
ALT246, ⌥ / 
× 
product, multiplication, times, 5×4=20 

𝑥 
italics x 

ℯ 
base of natural logarithm e 

𝒾 
italics i, imaginary number 

∘ 
function composition, as in f∘g 

∫ 
Integral for calculus 
⌥ b 
≈ 
approximate, as in π ≈ 3.14 
⌥ x 
≠ 
not equal to, as in 1+1≠3 
⌥ = 
≡ 
modular arithmetic congruence 

≅ 
geometry congruence 

± 
plus or minus 
ALT241, ⌥ + 
∙ 
multiplication dot or bullet 
ALT0149, ⌥ 8 
⟌ 
long division operator 

≥ 
greater than or equal to 
ALT242, ⌥ > 
≤ 
less than or equal to 
ALT243, ⌥ < 
∪ 
UNION, interval notation, "Joining" 
ALT8746 
⋂ 
INTERSECTION, interval notation, "overlap" 
ALT8745 