Being physics trained, we would do a problem like this:
$v=\frac{d}t$
$ =\frac{2 m}{4 s}$
$ =0.5 ms^{-1}$
Of course, being physics trained, we didn't always hold to the full conventions of mathematics. However, I am now being told to teach the problem like this:
$v=\frac{d}t$
$ =\frac{2}{4}$
$ =0.5 ms^{-1}$
That is, without the units in the problem until the end. Now I argue that the units help see where mistakes can occur - you can follow the units as a quick path to find where an error has crept in. However, I have been told that it is "not mathematical convention" to use units throughout. Is that correct? If so, why?