My calculator did ruin my ability to do mental arithmetic, because I had it in my pocket basically every weekday between the ages of 11 and 17. Damn school blaz

My calculator did ruin my ability to do mental arithmetic, because I had it in my pocket basically every weekday between the ages of 11 and 17. Damn school blazers and their capacious pockets. My general ability to do maths (in terms of understanding and applying mathematical concepts) is good, I got a degree in computer science, but my ability to do maths in my head is really bad.