Yes.
2469135780
456 + 789 + 123 + 123456789 = 123458157
111111111111111111111234
1234567890 + 1098765432 = 2333333322
123 plus 88 equals 211
Yes.
1 plus 1234567890 is 1234567891
2469135780
456 + 789 + 123 + 123456789 = 123458157
123
I have discovered a marvellous proof of this which this page is too small to contain...
111111111111111111111234
126
1234567890+9876543210=11,111,111,100
1234567890 + 1098765432 = 2333333322
4000 + 1234567890 = 1234571890