Try And Litre Down Gently

(My sister is at school, struggling to grasp how to convert pints into litres.)

Teacher: “Milk cartons from the supermarket come with both litres and pints marked on the bottles, don’t they?”

Sister: “Yes.”

Teacher: “So when you got to the supermarket, which milk do you pick up?”

Sister: “Semi-skimmed?”

Teacher: *wide-eyed and at a loss for words*