got the answer for you....
whatever two digit number you select, your answer will be always among following numbers... 81(90-99),72(80-89),63(70-79),54(60-69),45(50-59),36(40-49),27(30-39),18(20-29),9(10-19),0(00-09)... If you look at chart then all above number will have always same symbol and as you know it is different everytime you refresh it.