Filter based on a value from dropdown menu and list value's

I am not sure how to explain this issue, but I have created a dynamic dropdown list and it shows a certain value, which is working. 

I have a second tab that contains a list of value's with a certain number.

for example

cell A1 contains an explanation and A2 contains a number 

If a for example the number matches what I get from the dropdown list, it should give me the " explanation" in call A1

I have the feeling the formula "IF" should be used , but its more complex

any idea's?