Thank you for the opportunity to help you with your question!
To find the reciprocal of a number is found by switching the numerator and the denominator of a number. If we have a whole number like 4 in this case, it is always over an invisible 1. (It can be the same for 1,2,3,... and etc.)
So we need to look at 4 as 4/1. Now we will flip the numerator and the denominator. This will give us 1/4.
So the reciprocal of 4 is 1/4.
Please let me know if you need any clarification. I'm always happy to answer your questions.