[richajak]

I recently realized that I slowly lost my ability to do simple calculations that was used to be easy, eg total bill of grocery shopping before going to the cashier. I put the blame to the calculator app on my phone

[foxdev]

I could never do math in my head like this (with reasonable speed and accuracy), so I didn't lose anything.

I put an estimated cost by each item on the grocery list, total it at the bottom, and note whether the real prices are higher or lower than the estimate as I get things. It's never happened, but I can at least know if the register total is at odds with expectations.