Psychologists have been trying to work out why mental arithmetic can bring us out in a sweat.

心理学家一直在试图弄清楚为什么心算能让我们汗流浃背。

Gilbert Blythe spelled her down in class and left her clear out of sight in mental arithmetic.

吉尔伯特·布莱斯在课堂上把她拼写得很差，并在心算时让她远离视线。

They say it more precisely determines canine age. Their new method requires a little more than simple mental arithmetic to work out a dog's age.

他们表示，这种公式能够更准确地计算狗狗的年龄。他们的新方法需要比简单的心算稍微复杂一点的方法来计算狗狗的年龄。

“Mental arithmetic also requires the ability to retain order information in the short-term via rehearsal, and may be similarly affected by their performance in the presence of changing-state, background environments, ” he added.

“心算也需要通过练习在短时间内记住信息的顺序，因此也可能受到背景环境的影响，”珀罕补充道。

Paul did the mental arithmetic, said: " That's three short." " Why don't they have two carryalls to each crawler? " barked the Duke.

保罗心算了一下， 说：“少了三个。 ” “他们为什么不为每个爬行者配备两个手提包？ ” 公爵咆哮道。