205 - 147
Regrouping, we have:
200 + 00 + 5
-100 -40 - 7
----------------------
100 + 100 + 5
-100 -40 - 7
----------------------
100 + 90 + 15 (1 hundred 9 tens and 15 ones)
-100 -40 - 7
----------------------
100 + 100 + 15
-100 -40 - 7
----------------------
0 + 60 + 8
-------------------
60+8=68
