The mother took a cone-shaped glass. It fit evenly in this glass 20 grams of medicine. But the medicine was bitter. My little son persisted, that he would only drink half of the medicine: "O, so far!“- and showed with a fingernail a place halfway up the liquid in the glass.
The mother argued for some time, but in the end she relented and my son drank ,,half of the "medicine.".
Well, the doctor said to that?
— No, that's fine! The rest is for height 2 times smaller than the whole glass, but the volume is 8 times smaller. Little left 2,5 gram of medicine, and he drank 17,5 gram. He will be healthy!