How do I use the same math.random() number multiple times?

local RandomInteger = math.random(1, #AvailableItemsTable)

I have a variable, RandomInteger, that is supposed to save a random number between 1 and #AvailableItemsTable. Instead the variable RandomInteger saves the function math.random(1, #AvailableItemsTable), so every time I reference RandomInteger it gives me a new random number. Is there any way I can fix this so RandomInteger is actually a random integer that I can reference multiple times while still being the same number? Thanks for reading, any help would be greatly appreciated :)