It is the tradition of adding number 10 in the beginning and at the end .Hence the above number will be written in this way 10,6,10,7,5,1,4,8,4,10 10 -6(1 st pair) 6-10(2 nd pair) 10-7(3 rd pair ) 7-5(4 th pair) 5-1(5 th pair) 1-4(6 th pair 4-8(7 th pair) 8-4(8 th pair) 4-10(9 th pair) Sequence of the pair :(10,6),(6,10),(10,7),(7,5),(5,1),(1,4),(4,8),(8,4),(4,10)