1/ tinh : 1 giờ : 3= ...phút?
2/ lop 2a co 4 ban; lop 2b co 5 ban du thi violypic cap thanh pho . Cac ban cua hai lop bat tay chuc mung nhau moi khi di moi nguoi mot lan. Hoi co tat ca bao nhieu cai bat tay?Biết rằng các bạn trong cùng lớp ko bat tay nhau.
3/ so be nhat co 3 chu so khac nhau cua phep chia chu so hang tram cho chu so hang chuc bang thuong cua phep chia chu so hang chuc cho hang don vi la so.......
4/ cho day so :0,1,2,3,6,11,...So thich hop tiep theo cua day so do la:...
5/ so lon nhat co 3 chu so khac nhau ma tong cac chu so cua so do bang 21la:....
