Explicație pas cu pas:
Clasa 1
14+29=
65+78=
82-65=
44-22=
39+15=
Clasa 2
568+779=
678-123=
983-675=
112+998=
980-880=
Clasa 3
7628+6282=
7282-6829=
8192-7292=
8181+8292=
1818-1578=
Clasa 4
727282-518281=
727279+828181=
999999-777777=
819204+828286=
934703-382926