It is unnecessary to go to all that arithmetical trouble when there is a simple and more accurate way to get the result. 当存在一种简单而又更为精确的方法以得出结果时，再去用一系列麻烦的算术运算就毫无必要了。
A device used to perform arithmetic operations and is small enough to be conveniently placed on a desk. 用于进行算术运算并且小到可以很方便地置放台上使用的装置。
