What is 5.25 as a improper fraction?

To convert 5.25 to an improper fraction, first express it as a mixed number: 5 + 0.25. The decimal 0.25 can be written as 1/4. Therefore, 5.25 can be expressed as 5 1/4. To convert this mixed number to an improper fraction, multiply the whole number (5) by the denominator (4) and add the numerator (1), giving you 21/4. Thus, 5.25 as an improper fraction is 21/4.