To solve 159-73, a student writes the following equations:

160-70=90-3=87-1=86

Although the student has a good idea for solving the problem, his equations are not correct. In words, describe the student's solution strataegy and discuss why the strategy makes sense; then write a correct sequence of equations that correspond to this solution strategy. Write your equations in the following form

159-73=some expression

= some expression

= :

=86