To make it an improper fraction, you should most likely reciprocate it. Since we have a mixed number, you will multiply the whole number and the denominator, then add the numerator. 9 x 10 + 1 = 91. The denominator stays the same. 91 over 10. 91/10 is an improper fraction, because the numerator is bigger than the denominator.
Hope this helped, but Im not amazing at math