Ok, this is driving me crazy

I have a workbook with two sheets

Sheet 1, Column A has a list of arbitrary and repetitive values: 15, 18, 19,5, 23, etc...

Sheet 2 has the following:
Column A has a unique set of numeric values: 10, 20, 30 and so on
Column B has a text string associated to each unique value

What I want to do is the following:

Compare each cell on column A, sheet 1 to column A, sheet 2 (the complete list of unique values). In case there is a match, Sheet1, ColumnB should paste the text string associated to the value found on Sheet2. However, since column A has mostly arbitrary values, the probability of having an exact match are low, in which case what needs to be done is find the closest higher value in Sheet2, Column A; take the text string associated to it on Column 2 and paste it on Sheet1, Column2.

Any ideas???

Thanks!