Find Approximate Match

Dear all,

I have been trying to use vlookup to fin an approximate value and return the value in another column and keep getting NA error.

I have a range A1:A20 with numbers ranging from 0 to 1 and a range B1:B20 with sales. What I want to do is having in another part of the spreadsheet a list of values to lookup for example 0.2, 0.4, 0.6 and use the formula to look it up en A1:A20 and return the values en B1:b20 with an approximate match.

I have read it can be done combining Index and Match functions but I don't know how.

Thanks.