a. 4,5,6,7,8,9,,10,11,12,13.
2,3,4,5,6,7,8,9,10,11,12,13,14,15
8,9,10.
16,15,14,13,12,11.
b.7,6,5,4,3,2,1
2.3.4.5
10..9.8.7.6.5.4.3
4.3.2
c.27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10
3,4,5,6,7,8,9,10,11
81,80,79,78,77.76.75.74.73.72.71.70...........................10.9.8.7.6
d. 11,10,9,8,7,6,5,4,3
6,5,4,
8,7,6,5,4,3,2
5,4,3
2016,2015.................................10,9,8,7,6,5,4,3,2,1
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20..............................2010,2011,2012,2013,2014,2015