How do you change mixed fraction to improper fraction?

(taken off EHOW)

Multiply the whole number (7) by the denominator (4). In this case, 7 3/4 is our mixed number, so we will multiply 7x4. The product of 7x4 is 28.

Add the numerator (3) to the product (28) of the whole number and the denominator: 3+28. The sum of 3+28 is 31.

Make the sum (31), the new numerator in your improper fraction.

Keep the denominator the same as in the original mixed number: (4).

Your new improper fraction is the sum/denominator: 31/4. Thus. 7 ¾=31/4.