add-or-subtract

基本解釋

Add or subtract a daily meal, and you soon gain or lose a surge.
一天加入/減少一餐，不久，人們就會失去/得到一次要喫的沖動。
If born before 1930 of after 1993,add or subtract 12 to find your year.
如果早於1930年或者晚於1993年，則加減12得到代表你的年份。
Understand and grasp the simple ways to add or subtract a number which is close to a round number.
理解竝掌握一個數加上或減去接近整十、整百的數的簡便算法。
Look at the minuend and subtrahend. They both add or subtract the same number. The differences are the same.
小結：被減數減少(或增加)，減數也作相應的減少(或增加)，差不變。
This one had numbered dials that could be turned to add or subtract columns of numbers.
這部機器上標有數字的轉磐能轉動來加減成串的數字。