I was also wondering about this . When DS comes home with some tests from the previous week or when he's at home working on few things . He makes what i would call a silly mistake , because he knew well what the answer should be . In fact he's giving all the right answer when we went through some of those papers from school , and i kept wondering why .. why did you do this kind of mistake ? You understood the question , you knew the answer right , but why did you give the wrong answer ? He rushes when he's working on some tests at school , i have to keep reminding him to re-check his work during test . His answer " i think re-checking is a waste of time , mom " *sigh*
