correct algebric signs

[sal21]

I have two table in access database:
table
table1

table:
f1(text) f2 (numeric double)
AA -150
BB 25

ecc...

table1
f1(text) f2 (text)
AA +
BB -

Now i have see with attention in table the algebric signs are wrong!!!!!!!!!!!!!!!

How to correct the f2 in table based the new correct sign matching f1>f1 and return f2 of table with correct signs

in this case the new AA is +150 BB -25

With a query, please

Note:
i use jet ado conn and vb6 classic
f1 and f2 aere the name of fields in table
i can have in f2 of table a 0 (zero value)

[HansV]

UPDATE table1 INNER JOIN table ON table1.f1=table.f1 SET table1.f2=IIf(table.f2<0, "-","+")