How to use a cell in Excel that has a formula as a condition? -

i trying use formulated cell make condition, failed.

for example:

cell a1 contains number '12345'

in cell b1, insert '=left(a1,3)', returns '123'

in cell c1, insert '=if(b1=123,"yes","no")', should return yes, don't know why returns no.

any idea this? in advance

when use left function on number changes number text. try:

=left(a1,3)+0 

using math operation such "+0" change text number.