1000000000000000000000000000000000000 + 199999999999999999999999
bằng chính nó
==1000000000000199999999999999999999999
1000000000000000000000000000000000000 + 199999999999999999999999 = 1000000000000000000000000000000000000 + 199999999999999999999999 . Ok