Calculation With VARCHAR
Is this what you want to happen?

DECLARE @Test1 TABLE
(
  field1 VARCHAR(10),
  field2 INT
);

INSERT INTO @Test1 ( field1, field2 )
    VALUES ( '.05', 12 );

SELECT field1 / CONVERT(DECIMAL(18, 2), field2)
    FROM @Test1;


Since this was marked as the answer: I converted the integer value to a decimal because of data type precedence. The string '.05' can't be converted to an integer, but it makes a perfectly fine decimal.