1 con chim gap 1 dan chim bay nguoc chieu,con chim do noi:chao tat ca 100 ban chim ạ.1 con chim o dan ben kia dap:chung toi ko phai co 100 con.chung toi cong voi 1/2 chinh chung toi cong voi 1/2 chinh chung toi cong voi 1/4 chinh chung toi cong voi chinh ban moi bang 100.hoi dan chim do co bao nhieu con,hay trinh bay cach lam