Subtraction

This week Jackson's Studio (Rm 18) has been solving a maths question with subtraction. This is the question 57-29=

This is how I solved this question.

Equal Adjustments                       
57 -29=?  
+1  +1  
58-30=28  

Place Value

57-29=?

57-20=37

37-9=28

Hope you learnt something from this.

Thanks ^_^