Some insulin pumps these days have a feature that allows a child to input the number of carbs eaten, and the pump calculates the carb-to-insulin ratio based on what time of day it is. Most kids have at least three different numbers to divide the number of carbs by, and some have as many as nine different carb-to-insulin ratios – for example, if today’s snack is during soccer practice, it gets divided by one number, but if tomorrow’s snack is during study hall, it gets divided by another...