Năm 1980 có bao nhiêu ngày Thứ 6

4/1/1980 11/1/1980 18/1/1980 25/1/1980 1/2/1980 8/2/1980 15/2/1980 22/2/1980 29/2/1980 7/3/1980 14/3/1980 21/3/1980 28/3/1980 4/4/1980 11/4/1980 18/4/1980 25/4/1980 2/5/1980 9/5/1980 16/5/1980 23/5/1980 30/5/1980 6/6/1980 13/6/1980 20/6/1980 27/6/1980 4/7/1980 11/7/1980 18/7/1980 25/7/1980 1/8/1980 8/8/1980 15/8/1980 22/8/1980 29/8/1980 5/9/1980 12/9/1980 19/9/1980 26/9/1980 3/10/1980 10/10/1980 17/10/1980 24/10/1980 31/10/1980 7/11/1980 14/11/1980 21/11/1980 28/11/1980 5/12/1980 12/12/1980 19/12/1980 26/12/1980