Hey there!
The product of a number and 18 means you multiply that number times 18; the result is called the product.
When we multiply a number times a variable, we always write the number before the variable.
For example, we multiply 4 times d, and the result is 4d.
Let's check the options and see if we can spot something like "5a"
The first option: we multiply 18 times the difference of b and 18.
The second option: we add 18 and b
The third option: we divide 18 by b
The fourth option: we multiply 18 times b (That's the right option! We did it :)
Hence, the answer is
[tex]\boxed{\boxed{\bold{18b}}}[/tex]
Hope everything is clear.
Let me know if you have any other questions; if so, please comment.
#LearningDoesn'tEnd
#LearningIsFun
[tex]\rule{200}{2}[/tex]
