T?p con c?a t?p h?p A là t?p h?p g?m các ph?n t? ??u là ph?n t? c?a t?p h?p A.T?t C?Tin H?c L?p 6Tin H?c L?p 7Tin H?c L?p 8Tin H?c L?p 9Tin H?c L?p 10Tin H?c L?p 11Tin H?c L?p 12T?t C?Th? D?c L?p 10Th? D?c L?p eleventh? D?c L?p twelfth? D?c L?p 6Th? D?c L?p 7Th? D?c L?p 8Th? D?c L?p nineT?t C?Th? D?c L?p 10Th? D?c L?p eleventh? D?c L?p twelfth?