Thanks very much for looking into this Reinout-g.
I hadn't worked out what those buttons did I will totally admit and I am grateful that you showed me but I have never been impressed with the calculator on this site.
It gives some really weird answers sometimes.
A day or 2 ago one of the kids was doing a combination question and this calculator gave a decimal answer.
It is not the first time that I have seen it do things like this.
I think that it was you who told me that you often use this calc and that is how you stumbled into the forum. That really surprised me, I didn't think the calc was very good.