Hi Susan:

LEFT(TRIM({Cust #}), 2) = "BE"

Or if you want to select the letters each time: LEFT(TRIM({Cust #}), 2) = QUERYSTRING("Enter first 2 characters","BE" )

The TRIM isn't really necessary in your case but it's good practice to include it. Remember to type in upper-case because I didn't include any logic to handle different cases.