Răspuns :
a)246+395=641 => 246=641-395 ; 396=641-246
b)742-487=255 => 742=255+487 ; 487=742-255
b)742-487=255 => 742=255+487 ; 487=742-255
a)246+395=641; 395=641-246
b)742-487=255; 742=487+255
b)742-487=255; 742=487+255