Answer: 23/4
Step-by-step explanation: To write a mixed number as an improper fraction, first multiply the denominator times the whole number and then add the numerator.
So here, we multiply the denominator, 4, times the whole number, 5, then we add the numerator, 3. So we have 4 · 5 which is 20 and 20 + 3 is 23. Finally, we put our new number over our old denominator and we have our answer which is 23/4.
You can double check your answer by asking yourself how many times does 4 go into 23 which is 5 times and there's a remainder of 3.
I have also shown my work in the image attached.