>>> And, for some reason, I think it's an American poster
I hope it is. We were told to totally abandon feet and inches, in favour of solely using metric measurements, when I started at secondary school - and that was 55 years ago!
I also hope that the poster is still at school. We were doing this type of basic maths when I was about ten years old.
Buen…..this is pre 11+ stuff in my time. I would have done this in my head aged 9. No kidding. Is the poster pre secondary school? Is the poster far better with the written word than with basic addition and subtraction? Wind up or worse. Haha. Love it.