I ran into this one on twitter:

The ones where you combine numbers (use them all once) and operators to make a result,
should be easy for us Calcudoku puzzlers:

https://www.instagram.com/p/ChH4P_Fs1sN/

Just had a look at that puzzle and it seems to me that you can only find four solutions if you apply the operators sequentially or allow brackets. For example, 11 - 2 x 3 = 5 if you follow the normal convention of applying multiplication and division ahead of addition and subtraction. So you need to either express it as (11 - 2) x 3 = 27 or 11 - 2 = 9 followed by 9 x 3 = 27.

I've been watching a lot of Countdown lately and the possibility of not allowing you to input your own brackets didn't even occur to me. But yeah, that's very much a necessity here.

This was leading up to this puzzle, more challenging and interesting:

https://www.instagram.com/p/ChZP-kcLEcu/