a) a + 2 570 -1 221 = 3 427
a+1349=3427
a=3427-1349
a=2078
b) b + 4 326 – 2 322 = 4 333
b+2004=4333
b=4333-2004
b=2329
c) c – 2 456 + 2 457 = 4 987
c+1=4987
c=4987-1
c=4986
d) 1 346 + d - 4 732-1310 = 1 000
1346+d-(4732+1310)=1000
1346+d-6042=1000
d=1000+6042-1346
d=7042-1346
d=5696
3. a+3427-1270=3450
a+2157=3450
a=3450-2157
a=1293
Deci numarul este 1293