To convert a mixed number to an improper fraction, you multiply the whole number by the denominator of the fraction and then add the numerator.
For 3 1/2, you would multiply 3 (the whole number) by 2 (the denominator), and then add 1 (the numerator).
So, 3 * 2 + 1 = 7.
Therefore, 3 1/2 as an improper fraction is 7/2.