Just as some people are born colour-blind, or lose colour vision after a brain injury, others are "number-blind" : unable to comprehend what everyone else sees effortlessly.

正如一些人是先天性色盲或者脑部受损后失去颜色知觉，世界上也存在另一些人患有“数字盲”：即无法理解那些平常人觉得毫不费力的事物。