If you need a calculator for the easiest quick guesstimates, you are handicapped. If you start from day one with offloading every calculation to a calculator, you will be like that.

It is not a functional calculator and can’t be used as such. Learning how to use a simple calculator doesn’t require much training or special skills, that children of that age wouldn’t have already aquired by other means anyway. The important skill broken calculators learn is to analyze the problem and predict solutions in your head.

You could achieve something similar by giving pupils just a piece of paper and the numbers and signs they are allowed to use. The calculator part makes checking easier, yes. That’s about it.

A “broken calculator” isn’t a calculator. It requires you to calculate in your head to be effective, which is exactly what I was talking about.

First you need to solidify this ability, before it makes sense to introduce reliance on calculators.

There is no good argument for including calculators before the pupils haven’t mastered basic calculations in their head, there are good arguments against it.