打算盘 To calculate
【注音】dǎ suàn pán
【解释】算盘曾是账房先生不离手的东西，算盘打得好，账务一定也管得好。因此好的账房先生也有“铁算盘”的说法。现在算盘被计算器代替了，但是“打算盘”这个词仍保留了下来，不过表示的意思是筹划或计算得失。
Abacus was the old calculator for the accountant in the past, a good accountant must be good at using abacus, therefore, “an iron abacus” was a compliment for a good accountant. Now that abacus has been replaced by calculator , this term was still in use, only that the meaning has changed into being calculating, or petty and scheming.
【例子】
例1：李太太真会打算盘，买一斤排骨可以做好几个花样来吃，一家人好几天都在吃肉。
Ex.1：Mrs. Li is really a shrewd lady. She can cook one jin of ribs into various dishes and feed the whole family with meat for a couple of days.

例2：我希望你仔细地考虑一下，不要打错了算盘。
Ex.2：I advise you to think it over, don’t miscalculate.

打退堂鼓
retreat
【注音】dǎ tuì táng gǔ
【解释】古代官吏办公完毕离开办公室时，是要打鼓的。现在打退堂鼓表示遇到困难，中途退缩或改变主意。
In ancient times, when officials finish work and leave office, there will be a rite of drum beating. Now this expression indicates giving up middle way or back out in the face of difficulty.
【例子】
例：小朱准备了半年的托福考试，到了快要考试的时候又打退堂鼓了。
Ex.：After spending six months preparing for the TOEFL test, Xiao Zhou gave up at the last moment.