There are three representations of multiplication symbols, one is a cross, the other is "*" and the other is "*".

It is quite popular to use ""to represent multiplication. At present, schools in continental Europe (Germany, France and other countries) stipulate that ","is a multiplication sign. Other countries use "×" as multiplication sign and "×" as decimal point. Our country stipulates that "×" or "×" can be used as a multiplication sign, and the multiplication sign before letters or brackets can be omitted.

Complete works of mathematical symbolic induction

1, geometric symbol

⊥、∥、∠、⌒、⊙、≡、≌、△。

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

|a|、⊥、∽、△、∠、∩、∪、≠、≡、、≥、≤、∑、↓.