bài 2: tính nhanh :
a) 3/8 + 7/12 + 10/16 + 10/24        b) 4/6 + 7/13 + 17/9 + 19/13 + 1/9 + 14/6 
                     
               c) 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 

a) 4 3/8 + 5 2/3                        b) 2 3/8 + 1 1/4 + 3 6/7                           
c) 2 3/8 - 1 1/4 + 5 1/3             d) (5/2 + 1/3) : ( 1 - 1/2)     
e) (5/2 - 1/3) x 9/2 - 6/7

đặt câu hỏi cho phần in đậm
1. They often go to the park at weekend.
2. She usually chats with her friends at recees.
3. Tung travels to work by motorbike.
4. We are learning English at the moment.
5. She is visiting his grandparents this weekend.