Hi, before submitting a feature request, I'd like to check whether I just don't see existing options.

The task is to check for correct mantissa but wrong order of magnitude for input with units.

I know how to do this for numeric input.

**Question variables**

`mantissaOK(x,y,tol):= is(abs(round(log(x/y)/log(10))-log(x/y)/log(10))<tol);`

**PRT**

- AlgEquiv:
- SAns:
`mantissaOK(ans1/tans1,0.005)`

- Tans:
`true`

- Feedback for true: Mantissa is correct but the value is off by at least an order of magnitude. Check your units handling.

- SAns:

My impression is that equivalence of units is only handled inside the Unit... answer tests. For the above order of magnitude test I need an algebraic equivalence test, which doesn't seem to cancel MPa against N/mm^2.

Is there a way to simplify expressions like MPa/(N/mm^2) to 1?

Being wrong by some orders of magnitude is a very common error, so I'd like to include such tests by default in formative feedback.