VB codes for excel

Hello,
I'm trying to write a Macro that will search an excel spread sheet and display the adjacent cells. I have a series of increasing but not sequential numbers in column C and I want the macro to compare the input and find the first value that it is less than. Once it has found this value I then want it to display the numbers in Colum A and B in the same row.
I've tried a number of things but I’m not really getting anywhere
Any help would be greatly appreciated.