SUMIF(range,criteria,sum_range)

Where string (cell formula) criteria is tested against the string in
the "range". This test is a full string comparison.

How do I write the formula so that the full "criteria" string is
tested against a subset of the string in "range," e.g. LEFT(range,2)?

LEFT(range,2) per se doesn't work.

Basically I'm subtotalling data by accounting classification, which is
a four digit string of ciphers. The SUMIF function works fine for me
to subtotal, e.g., all of the entries for which the Account No. is
"1234". I want to run a separate subtoatl of all of the entries for
which the Account No. begins with "12". And I explictly want to
calculate it in this fashion, not by adding the indvidual subtotals
that have been generated.

TIA

Fred Holmes