______ _____ _____
2abcd3=? stiind ca 2abcd+abcd3=63651
2abcd+
abcd3
---------
=63651...=> d=11-3...=> d=8
2abc8+
abc83
--------=
=63651...=> c=15-1-8...=>c=14-8...=>c=6
2ab68+
ab683
----------
=63651...=> b=16-1-6...=>b=15-6...=>b=9
2a968+
a9683
----------
=63651...=> a=13-1-9..=>a=12-9...=>a=3
23968+
39683
--------- ______
=63651.....=> 2abcd3=239683