3.) 12 300+a=12 404
a= 12 404-12 300
a= 104
45.789-b=45.505
b= 45.789-45.505
b=284
c+ 23.456=23.616
c=23.616-23.456
c= 160
d-84=64
d= 64+84
d=148
104+284+160+148=696 ( pagini au in total cartile de pe raft ).
5.). 36145+24542=60687( suma )
36145-24542=11.603( diferenta )
60687+11603=72290
6.). 43000+ 42999=85. 999
85.999-12.500=73.499