Split pea soup

I downloaded a pea and ham soup recipe from good housekeeping. The first hurdle was no dried green peas in the shop, I had to get yellow ones. Then the quantities were bizarre. I should have realised when it said 1 litre was 3 pints. (1.7 L really)  Anyhow I followed the recipe, 1 litre, it came right to the top of the slow cooker. I had to boil some of it separately. It ended up using more energy instead of saving it. 
Luckily it was was very tasty.
Joe was top of year 4 for maths, he said it was times tables. He’s very happy about it.