Solution

0111
+6789
0789
07578

Step 1

1
+6789
0789
8
9 + 9 = 18
Carry= 1
Unit Value = 8

Step 2

11
+6789
0789
78
8 + 8 + 1 = 17
Carry= 1
Unit Value = 7

Step 3

111
+6789
0789
578
7 + 7 + 1 = 15
Carry= 1
Unit Value = 5

Step 4

111
+6789
0789
7578
6 + 0 + 1 = 7
Carry= 0
Unit Value = 7

Step 5

0111
+6789
0789
07578