A bond dealer need not appreciate Proust, but he must be able to do sums in his head.
一个债券经销商不需要感激蒲鲁斯特，但是他必须能够心算。He said if he can't do them in his head, I'm cheating.
他说既然他都不能心算我肯定是在作弊But to make my job more interesting for you, as well as for me, I'm going to do this problem thinking out loud.
为了给大家和我自己增加点乐趣，我会把心算过程大声的念出来。Any system of counting or calculation, whether mentally of by means of device, involves following a set of steps or directions.
任何一种计算系统，无论是心算还是借助于设备，都包括下述的一套步骤方法。OK, what I'm going to try and do, is to square in my head a five-digit number requiring a 10-digit calculator.
很好，我接下来要做的是，心算平方一个5位数的数字，这需要个10位数的计算器。It is not significant when mental arithmetic problems are simple, but it becomes more significant with the difficulty growing.
数学焦虑对简单心算问题的影响不大，随着问题难度的增加，数学焦虑效应逐渐明显。For him, doing mental calculations was a form of play.
对于他来说，做心算就如游戏一样有趣。But Carroll was the first person to devise an algorithm suitable for mental calculation.
但是卡罗尔的算法确实第一个适合心算的。He mentally computed the square root of a hundred-digit number in fifty-two minutes.
他在52分钟内心算出了一个100位数的平方根。