⊥ ∥ ∠ ⌒ ⊙ ≡ ≌ △

2. Algebraic symbols

∝ ∧ ∨ ~ ∫ ≠ ≤ ≥ ≈ ∞ ∶

3. Operation symbols

Such as plus sign (+), minus sign (-), multiplication sign (× or), division sign (÷ or/), union of two sets (∩), intersection (∩), root sign (√), logarithm (log, lg, ln) and ratio (:).

4. Symbol set

∪ ∩ ∈

5. Special symbols

∑π(π)

6. Inference symbols

Index 0 123: O 123

7. Symbol of quantity

Such as: I, 2+i, A, X, natural logarithm base E, pi.

8. Relationship symbols

For example, = is equal sign, ≈ is approximate sign, ≠ is unequal sign, > is greater than sign,