I created this after a discussion on Twitter.
Estimating is more complicated then I give it credit for. We have to decide the level of rounding that’s appropriate, based on the calculation being done. It’s not just as simple as rounding to 1 s.f.
I did some questions that are quite typical. Check the calculation by estimation.

Then I did some ones where we need to work it out.

And an emoji based exam question format I quite like

There’s nothing new here, nor anything really ground breaking. But it quite a bit more thorough than I have been in the past, which pleases me.