[(c - 299 : 23) : 4 + 239 ] • 16 - 1 999 = 1 905
[ ( c - 13 ) : 4 + 239 ] • 16 = 1 905 + 1 999
[ ( c - 13 ) : 4 + 239 ] • 16 = 3 904
( c - 13 ) : 4 + 239 = 3 904 : 16
( c - 13 ) : 4 + 239 = 244
( c - 13 ) : 4 = 244 - 239
( c - 13 ) : 4 = 5
c - 13 = 5 × 4
c - 13 = 20
c = 20 + 13
c = 33 → numarul aflat prin metoda mersului invers