This was pretty straightforward – which was a relief after the difficulties and ultimate failure with Day 9. I also got to use a cool new trick with the GREL cross function that I literally just learnt about. I made a silly mistake not reading the instructions quite carefully enough which led to an “off by one” error, and I faffed a bit getting the sum (as an aside it’s a shame that a sum across rows is required so often in these problems just to give a simple number to type in as an answer – this isn’t OpenRefine’s strength and it isn’t really the crux of the problem).