FOR THE STUDENT OF MATHEMATICS
DEMONSTRATION CLUB FILE XXIV


PURPOSE: To demonstrate that for real number x, real number y, real number w and real number z:

                    XXIV.     If x = y and w = z then x + w = y + z.

is true.



DEMONSTRATION:     STATEMENTS                                       REASONS



                            1.     x + w = x + w                     1.       Property XII   Reflexive:   p = p

                            2.     x = y and w = z                   2.     Given ( from the hypothesis or "If" part of the statement. )

                            3.     x + w = y + z                       3.     Property XVIII   Substitution of y for x and z for w



Equal's added to equal's are equal's.     [ ='s + ='s are ='s ]

What about:   "Equal's subtracted from equal's are equal's."   ? So!

    Property XXIVa.     If x = y and w = z then x - w = y - z.


Would you like to demonstrate Property XXIVa. ?

Properties:     List #1 Link     List #2 Link     List #3 Link     List #4 Link     List #5 Link   and   Demonstrations

Copyright © 2009 with all rights reserved by William V. Thayer         Assisted by Peter Rankin, Demo Club Member