The Importance of Base Numbers

I think the I for me to be kind of three stages of this the kids would start off doing the double digit addition and then we'd establish very quickly which kids are comfortable and which kids aren't. If I said to them again just top of my head how many different sums can you make the double digits sums that the add up to eight eight and maybe I'll put a constraint in there maybe something like the sum of the four digits must be a prime number or something like that. Yeah I think ETL Draw I think he's still at Southampton University his phrase is is perfect where he talks about just right challenge. We're always trying to create this just right challenge that they go over