Answer Addition: a + b. The operation sign is +, and is called the plus sign. Read a + b as "a plus b."
1) For example, if a represents 3, and b represents 4, then a + b represents 7.
2) Subtraction: a − b. The operation sign is −, and is called the minus sign. Read a − b as "a minus b."
1) If a represents 8, for example, and b represents 2, then a − b represents 6.
3) Multiplication: a · b. Read a · b as "a times b."
The multiplication sign in algebra is a centered dot. We do not use the multiplication cross ×, because we do not want to confuse it with the letter x.
And so if a represents 2, and b represents 5, then
a · b = 2 · 5 = 10.
"2 times 5 equals 10."
Do not confuse the centered dot -- 2·5, which in the United States means multiplication -- with the decimal point: 2.5.
However, we often omit the multiplication dot and simply write ab. Read "a, b." In other words, when there is no operation sign between two letters, or between a letter and a number, it always means multiplication. 2x means 2 times r:
Explanation: