possible to pull in a value from another form

possible to pull in a value from another form

i'm trying to create a formula that takes into account a field on form a and a field in form b. however, i know that isn't possible.

form a.field 1 * form b.field 1 = formula

the workaround is for me to create a second field in form b (form b.field2) that i essentially want to duplicate form a.field1.

form b.field 2 * form b. field 2
form b.field 2 = form a.field 1

i'm trying to figure out how to have form b.field2=forma.field1. can't figure out if there's a simple set variable script that will allow for that. or if i need to do a lookup. i tried doing a lookup, but then ran into an error msg that said:

variable is of type string but integer was expected.

help appreciated!