? -a - a $$- a$$ ? E=mc^2 E = m c 2 $$E = m c^2$$ ? e^(ipi)=-1 e i π = - 1 $$e^{i \pi} = - 1$$ ? a !<= b !>= c a ! b ! c $$a ! \leq b ! \geq c$$ ? a!=0 a 0 $$a \ne 0$$ ? ax^2+bx+c=0 a x 2 + b x + c = 0 $$a x^2 + b x + c = 0$$ ? x^2+y_1+z_12^34 x 2 + y 1 + z 12 34 $$x^2 + y_1 + z_{12}^{34}$$ ? x^2+y_1+z^34_12 x 2 + y 1 + z 12 34 $$x^2 + y_1 + z_{12}^{34}$$ ? a//b a / b $$a / b$$ ? sqrtsqrtroot3x x 3 $$\sqrt{\sqrt{\sqrt[3]{x}}}$$ ? abc-123.45^-1.1 a b c - 123.45 - 1.1 $$a b c - 123.45^{- 1.1}$$ ? stackrel"def"= = def $$\stackrel{\mbox{def}}{=}$$ ? \stackrel{\Delta}{=}" "("or ":=) = Δ ( or := ) $$\stackrel{\Delta}{=} \mbox{ } ( \mbox{or } := )$$ ? {::}_(\ 92)^238U   92 238 U $$\mbox{}_{\, 92}^{238} U$$ ? a_(mn) a m n $$a_{m n}$$ ? a_{mn} a m n $$a_{m n}$$ ? sqrtx x $$\sqrt{x}$$ ? x^2 x 2 $$x^2$$ ? S' S ' $$S '$$