(A) the usage is different

1, dot-multiply symbol:

In algebra, two rational numbers are multiplied by parentheses, or numbers by letters, or letters by letters. The symbol ""is usually used, or the multiplication symbol is omitted. For example:? (-3)×(-5) can be written as: (-3) (-5); ? 3×a can be written as: 3.a or 3a.a multiplied by b can be written as A.b or ab.

2. "×" multiplication symbol

When a number is multiplied by a number, you must write "X", but you can't write a dot or omit it. For example, 2X2 cannot be written as 2.2 or 22.

(B) the founders are different

1 and "×" denote multiplication, which was initiated by British mathematician Oughtred in 163 1. He found that multiplication also means addition. Rotate "+"by 45 degrees, and use "x" diagonally to represent multiplication.

2. It means that multiplication was initiated by mathematician harriot.

(c) The confusing aspects are different.

1, the multiplication sign "x" is very similar to the Latin letter "x", which is easy to cause confusion.

2. The multiplication sign ""is similar to the decimal point, which is easy to cause new confusion.

Second, the use of multiplication symbols

1, "Find the sum of several identical addends" is more convenient to calculate by multiplication, and you can use a multiplication sign, for example, the sum of seven twos can be 2×7? To show. 2 is the same addend. 7 is a number of 2, and 2×7 represents the addition of 7 2. Because the sum of seven twos is equal to 14, 2×7 is also equal to 14.

2, multiplication can also be used to calculate the rectangular area, area = length × width.

References:

Baidu encyclopedia-multiplication

Baidu encyclopedia-multiplication sign