ifactor(Ans) does not work

[retoa]

Thank you very much to all,

I did not think about the 2 different Ans (Home and Cas).
So as I tried I probably had a value in the Cas Ans that could not be passed to the ifactor function and that caused the error.

I find this a bit confusing. If I calculate 3*5 in Cas then go back to home calculate 3*7 and then I do ifactor(Ans) I find 3*5. This is the right answer because it is the factorisation of 15, the last Cas result, and not of 21, the last Home result.

Quite odd... I can understand that this is right, but if you don't notice you are using a Cas function in home (if you take it from catalog you don't see the CAS.-) you go up with an answer that is not the one you are looking for...

Reto