You’re ending up with a larger group of pupils “mastering” basic calculations through counting, when you remove the calculator as a tool for learning. Using the strategy of “counting all”, is one of the clearest signs a 1st grade pupil will be behind their peers in 4th grade. Broken calculator (just search for it), is one way to include calculators in a didactic way. But using calculators in general, improves a kids ability to estimate results - Which is an ability that helps anyone out tremendously, as it’s giving you a clear idea if something went completely wrong in a calculation