vt.　减 take a number or quantity away from another number, etc.

　～ from　从…中减去
　～ five from ten　十减五

　Please subtract a quarter of the money for your own use.　请从你零用钱中扣除四分之一。
　From this amount you need to subtract something to cover fixed overheads.　你需要从总数中扣除一些钱去维持企业的正常运作。

 ♣ subtract from　(v.+prep.)
1. 从（大数字）中减去（较小数字） take (a smaller number) away from (a larger number)
　He subtracted 89 from 200.　他从200中减去89。
　If you subtract 2 from 7, the answer is 5. 　7减2答案是5。
　A week later, read the water meter again and subtract the first reading from the second.　一星期后，再看一下水表，然后从第二次读数中减去第一次读数。
2. 下降，降低 be lower
　That will subtract nothing from his merit.　那将无损于他的美德。

 ♣ subtract, deduct
　这组词都可表示“减”“扣除”。其区别是：subtract主要指数学上的“减去”，即甲数被乙数“减”; deduct指从全部〔整体〕（如工资、花费）中扣除某一部分。