The tiniest calculator app ever (<12MB), but no M+
It’s clear that you might not add all normal iPhone calc features to 12 MB app, but the basic standard intuitive shapes and colors for buttons would make it more attractive even without adding another basic feature for memory (M+, MC, MR). And I still wonder why is it still a taboo to make a plain copy of iPhone’s calculator app for iPad. I would even donate some money for that too.