Final answer:
An expression to check if the int variable gross_pay is less than 10,000 would be written as 'gross_pay < 10000' and would evaluate to True if the condition is met.
Step-by-step explanation:
The student is asking for an expression that evaluates to True if the int variable gross_pay is less than 10,000. To write this expression in a programming language like Python, you would use a comparison operator. The expression would simply be:
gross_pay < 10000
This expression compares the value of gross_pay to 10,000 and evaluates to True if gross_pay is indeed less than 10,000, or False otherwise.