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(huì)失去/得到一次要吃的沖動(dòng)。
If born before 1930 of after 1993,add or subtract 12 to find your year.
如果早于1930年或者晚于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.
理解并掌握一個(gè)數(shù)加上或減去接近整十、整百的數(shù)的簡(jiǎn)便算法。
Look at the minuend and subtrahend. They both add or subtract the same number. The differences are the same.
小結(jié)：被減數(shù)減少(或增加)，減數(shù)也作相應(yīng)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(jī)器上標(biāo)有數(shù)字的轉(zhuǎn)盤(pán)能轉(zhuǎn)動(dòng)來(lái)加減成串的數(shù)字。