Paid t-test result is the same as proc means t-test for the change score

Paired T-test returns the same results as the simple t-test.  Compare the results of PROC TTEST and PROC MEANS below.  The statistical test results are identical.

data exercise;
input Subject_ID $ Pretest Posttest Treatment $;
cards;
A 11 24 T
B 22 26 C
C 32 25 T
D 22 44 C
E 25 45 T
F 36 24 C
G 33 25 T
;
run;

data exercise2;
set exercise;
change=posttest-pretest;
run;

PROC TTEST;
paired pretest*Posttest;
RUN;

proc means data=exercise2 mean std min max n stderr prt;
var change;run;