Using a calculator to mark work

I am in a privileged situation these days of watching many mathematics lessons and September tends to consist of a lot of number work.  I know that in an ideal world all students would be able to do all calculations fluently in their head or on paper, but I wonder how much this happens these days outside of the school environment as most of us carry a calculator on our mobile phones.  In the lessons I watch, I rarely see a calculator used at all and often hear "you don't need a calculator for that".  

In cases where the calculation is not the key skill being learned, I wonder why not?

How many times do we hear students saying "I don't need a calculator" and then watch them do a long calculation to get to an answer that would have taken seconds on a calculator.

How many times do we hear that using a calculator is "cheating".

And is there a way to change this? I believe so.

Are the answers written on the board or read out by the teacher towards the end of the lesson? Too late then to fix any mistakes.

Instead we could get pupils to work out the answer on the calculator and mark their work.  This not only gives pupils instant feedback but starts to get them calculator fluent.

Remember that year 7 may never have used a calculator in class before and now you are letting them use it to mark their own work!

Have you ever watched pupils who seem to struggle to even find the basic numbers? It could be to do with the fact that the numbers on a calculator are in a different order to those on a phone keypad.

The picture on the right here from the Casio fx-83GT CW shows that just in this small part of the calculator there is a lot of new buttons that pupis may not have seen before. Especially as this calculator has no equals sign but instead has an execute button.  Answers to numbers that are not integers are shown as fractions and need to be converted and unlike previous versions of the calculator there is no SD button.  

Using calculators to mark basic calculations allows you to teach these calculator skills alongside what pupils will see as traditional learning.  Hopefully then using a calculator will just become part of the every day routine in the classroom and allow students to become more independent, and have a way to self assess their work.

I am therefore not saying don't teach pupils how to work out calculations in their head or on paper, but I am saying to teach calculator skills in parallel and not as a separate event.

When I suggest this to teachers they often ask questions like "But how do I stop the pupils just using the calculator to do the question". I can see why this question is asked but feel that this comes from lack of use of the calculator.  One head of department I work with stated that "using a calculator should not be a surprise, it should just be the norm".  And I think they are correct, the more we use a calculator as just another tool in the classroom the less it will become cheating and the less it will become a toy.