Doctors often use fractions to figure out what the right dose is. There is a medicine that can treat patients who are having a stroke (a blood clot that stops blood flow going to part of the brain). The dose of the medication is (9/10) times the body weight in kilograms. So if a patient weighs 70 kg, doctors have to multiply 99/100x (70) = 63 mg of medication. Then (1/10) of that is given right away (6.3 mg), followed by the rest (63-6.3=56.7 mg) over an hour. The nurses who give the medication have to do more to figure out how much medication has to be given every minute on a pump. If there is a math mistake, then the patient might get too little medication-then it probably won’t work. If they get too much medication, they might have bleeding in the brain. So doctors have to be sure they do it right. Calculators and several people do the math to make sure everyone agrees.