I would regroup because adding 43+28 in my mind is a little confusing, why bother when I can regroup and add (3+8) +40 + 80? And I could even regroup the 11 resulting from the 3+8, to make 10+40+80+1. Super easy now (you could even add the ten the the 80 first, and take a ten from 40 and add it to the new 90. 100+30+1! /Really/ easy now.).