Excel Help

Hello,

I have two worksheets. In the first worksheet I have 1 column (column a1) with numbers in them, on the second worksheet I have 2 columns with number (column "a" and "b"). I want a formula that will search for the numbers is column "a1" in the second worksheet in column "a", and if it finds a match I want it to insert the number that is in column "b" on the first worksheet.

So basically I have 2 lists. I want to match the information from both worksheets without me going through 10,000+ lines manually and insert the one column that I need to add. Some of the numbers that I am searching for from the first worksheet will not be in the second worksheet. The number that match I want the information that is in the next column of the second worksheet to show up in the first worksheet. I guess I need to match up all the information that is not in worksheet 1 to worksheet 2.