1. When we do subtraction, we take things away. ��������������ʱ������ȡ�����
2. We do addition and subtraction in arithmetic. ��������������Ӽ����㡣
3. Math Quiz Application - Math quiz program for addition, subtraction, multiplication and revision of wrong answers. ����һ����ѧ���ճ������ڼӷ����������˷��������Ĵ���𰸡�
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n.
1. an arithmetic operation in which the difference between two numbers is calculated
2. the act of subtracting (removing a part from the whole)