Dividing a number over multiple columns, but having the total in the columns add up to the dividend

I have a total number (55, for example). I want to divide that number by three and put the result (needs to be a whole number) into three different columns. But, the numbers in the three columns need to add up to the original number.

Let me give you the context. A 3rd grade in a building has a total of 55 students. We have 3 sections of 3rd grade. I want to have 55/3 ... in three columns (one for each section) and have a result of 19, 18, 18... to signify that each of the three sections will have 19 students, 18 students and 18 students. Is there a formula that will allow me to do this?

Thank you.