[psyang]

Originally Posted by delayedreflex

Spoiler!

I think that's the right idea, with one small change: 19 - 11 = 8 is doable with the "standard" 9, moving a stick from the equal sign over to the minus sign to swap those symbols.

I think full marks to Sebc as he got the "trick". Delayedreflex has the actual answer I was looking for.