Because "×" is easy to be confused with unknown X, and it is not convenient to type, so * is used instead of multiplication sign.

For example: 3*4= 12, 4*(3+6)=36.

"*" also means a number other than 0 in mathematics. For example, N* means a set of positive integers, that is, a set of all positive integers.

Extended data

The asterisk originated in feudal Europe, and genealogists wanted to indicate the date of birth. The original shape is six awns, each of which is like a teardrop scattered from the center. So some computer circles call it "splat" (pictophonetic character, similar to "pa" in Chinese).

Many cultures have their own unique asterisks. China and Japan use "※", which looks like the Chinese character "rice". The Arabic asterisk is a six-pointed star. In some fonts, the asterisk is five awns and the Arabic asterisk is eight awns.

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