Bai1 Rút gọn phân số :
42 phần 36 = :............................................................................... 64phan 80 = .............................................................
210 phan 300 =............................................................ 88phan 55=............................................
Bai2:Quy đồng mẫu số :
a. 2phan 3;3phan5;7phan10:......................................................................................................
b. 1phan3;3phan4;7phan5
Bai3:dien dau lon ,be hoac bang
7phan9............ 1 1........11phan14 16phan20.............4phan5 16phan 13................1 18phan 9...........3