In my 29 years in this business, I have seen the handheld calculator grow from a specialty tool used by few to an omnipresent device used as a crutch by many. When the calculator first entered the classroom, the intention was that it would allow the student to handle calculations in a manner previously not possible, either by the complexity of the calculations themselves, or by the quantity of calculations needed.
What I have seen, however, is the calculator invade human cognition as a virus might invade the brain, crippling students ability to do some basic calculations.
Arithmetic errors occur with greater frequency, largely due to the speedy rush to get a result: with a calculator there is generally no one to point out that you just dialed a wrong number.
Along the way, the calculator has instilled in many students the idea that in order for a number to be real, it either has to be a whole number or have a decimal point. A fraction is a number? Hogwash, they say. (Or whatever might be the current equal of 'hogwash".)
I see more and more students who look at anything even remotely appearing to be a fraction and just freeze. Fractions were always difficult for some, but that group is constantly expanding.
More on this later. This is just a beginning for a novice blogger.