Для повышения эффективности алгоритма добавлен массив sr, хранящий суммы по строкам.

DIM m AS INTEGER, n AS INTEGER
CLS
INPUT "m,n=", m, n
REDIM a(1 TO m, 1 TO n) AS INTEGER
REDIM sr(1 TO m) AS INTEGER
RANDOMIZE TIMER
FOR i = 1 TO m
   sr(i) = 0
   FOR j = 1 TO n
      a(i, j) = INT(RND * 20) - 10
      PRINT USING "####"; a(i, j);
      sr(i) = sr(i) + a(i, j)
   NEXT j
   PRINT
NEXT i
DIM k AS INTEGER
k = 0
FOR i = 1 TO m
   FOR j = 1 TO n
      IF a(i, j) = sr(i) - a(i, j) THEN k = k + 1
   NEXT j
NEXT i
PRINT k