In mathematics, when a number is multiplied by a variable in a term, the number part is known as the coefficient. For example, in the expression 5x, the number 5 is the coefficient of the variable x.
The coefficient indicates how many times the variable is being multiplied. So, if we have 3y, it means we have three times the variable y. This concept is essential in algebra as it helps to understand the relationship between numbers and variables in expressions and equations.