求整数四则混合运算中的未知数，可以运用逆运算关系解答。一、加法和减法互为逆运算，应用这种关系可以求出加、减法中的未知数。例１在下面算式的□里，填上合适的数，你能有几种填法？６×□＋□＝６分析与解：根据加、减法互为逆运算的关系，可将原式改写成□＝６－６×□ Find the four integer mixed integer unknown, you can use the inverse relationship between the solution. First, the addition and subtraction each other inverse operation, the application of this relationship can be calculated plus, subtraction in the unknown. Example 1 In the following formula to fill in the appropriate number, how can you fill in? 6 × □ + □ = 6 Analysis and settlement: According to Canada, subtraction each other inverse relationship between the original can be rewritten as □ = 6-6 × □