Match On Numbers With Diminishing Accuracy

I am interested in matching numbers. How to develop this:

=INDEX(All!E:E,IFERROR(MATCH(LEFT(B2,16)*1,All!A:A,0),IFERROR(MATCH(LEFT(B2,15)*1,All!A:A,0),
IFERROR(MATCH(LEFT(B2,14)*1,All!A:A,0),IFERROR(MATCH(LEFT(B2,13)*1,All!A:A,0),
IFERROR(MATCH(LEFT(B2,12)*1,All!A:A,0),IFERROR(MATCH(LEFT(B2,11)*1,All!A:A,0),

[Code] .....

It looks at what is in cell B2

It starts with the first 16 numbers and tries to match it with data in Col A of the sheet All!. If it finds a match it reports the data in the corresponding row of col E in sheet All.

If it cant match that it looks for the first 15 numbers and tries to match, then 14 then 13 etc etc.

Its often the case that the data in Col A of All is much shorter than the data in B2, so this works well.

The value in B2 is a telephone number. The values in Col A are Dial prefixes on a carriers rate card so the number is matched to the carriers rate card in the best way possible.

But I need to apply a different method for a different project.

The statement above gradually diminishes the accuracy of the number in cell B2

What I want to do is simultaneously diminish the accuracy of the two numbers to be matched.

For a successful match, the length of the number must be the same. So len(B2) must match len(matched cell).

But, the last number might not be the same. If there is no match, look at the numbers and see if there is a match if all the numbers are the same excluding the last 2 numbers in both, if no match, exclude the last 3 numbers in both, if no match exclude that last 4 numbers in both. Etc etc.