In the 2010, grade 6 have 50 good students, grade 7 have 120 good students, grade 8 have 150 good students, grade 9 have 350 students and it total of school is 670 good students all grade. But in 2011, there are 50 good students in 2010 increase to 100 good students, grade 7 have 120 good students are equal to the number of the good students last year, grade 8 have 150 good student's are decrease to 130 good students in the present, grade 9 have 200 remanings, it total of school is 550 good students all grade (còn lại em tự làm đi, anh mệt quá sorry, cái này anh làm hơi rối tí kiểu nêu ra số liệu chứ k làm thành đoạn văn đc)