Text Field Lisp??

Hi,

Attached is an imageof what I'm doing. I got lumbered with a task of checking some section drawings from some of the users.

Basically I was wondering if anyone had come up with something similar already.

In the picture, there are 3 circles in red and Labeled as 1 is a text object

Labeled 2 is a text object with a text field linked to a dimension 75.37 which is to the left of label 3 and formated to look like 0+075.37

Labeled 3 is also a dimension

I wish to be able if possible to replace the text in Nr 1 by selecting Nr 2 and 3 and have a text field inserted of a formula adding the values of 2 and 3.

If anyone can help or has any ideas or better solutions, that would be great.

Thanks

Heres a text1-text2 write aswer to text 3 change as required

(defun C:T1t2 ()     
   (setq text1 (entget (car (entsel "\nSelect text 1 "))))
   (setq anst1 (atof (cdr (assoc 1 text1))))      
   (setq text2 (entget (car (entsel "\nSelect text 2 "))))
   (setq anst2 (atof(cdr (assoc 1 text2))))
   (setq ans (rtos (- anst1 anst2) 2 3))
   (setq en (entsel "\nSelect destination text:"))
   (setq el (entget (car en)))
   (setq el (subst (cons 1 ans) (assoc 1 el) el))
  (entmod el)
  
  ;(entupd en)
) end defun
(PRINC)

Thanks for the code.

Unfortunately this is not what I am after or at least it doesn't do what I want it to do.

The first text that I select in the picture above is a text field, the second is a dimension. I need to create the third text as a text field formula, (text field 1 + dimension 2) so that if there are any changes to the other text fields or dimensions they will automatically be carried through the entire section drawing.