Answer/Step-by-step explanation:
A term in an algebraic expression is a number standing on its own (constant), a letter (variable), or a number multiplying a variable (coefficient * variable).
Given the expression, 9a + 4b - 18, there are three terms in the expression, namely: 9a, 4b, and -18.
The student made an error in identifying the terms properly by excluding the variables, a and b, in the first term (9a) and in the second term (4b), respectively.
The correct terms are: 9a, 4b, and -18.