substraction

基本解释

I can't understand so substract idea.
我无法理解如此抽象的观念。
Lucy knows how to add and substract but fractions have her up a stump.
做加减法，露西不成问题，可分数却难倒了她。
Children should be able to add and substract in the third grade.
儿童应该在三年级的时候能够进行加减运算。
Lets look at 2 examples, number 1 is a normal substraction, 2&3 are special.
让我们来看两个例子;(1)是普通减法;(2)和(3)是特殊算法.
Cyclamen persicum was carried on with substract culture testing by useing of different complex substrate.
摘要用不同复合基质对仙客来进行基质栽培试验。