To convert the mixed number 4 1/4 to an improper fraction, follow these steps:
1. Multiply the whole number by the denominator: 4 × 4 = 16.
2. Add the numerator to the result: 16 + 1 = 17.
3. The improper fraction is 17/4.
So, 4 1/4 as an improper fraction is 17/4.