It's a mathematic number series whose general formula is 99 - 11n where n can take any integer value between 0 and 8, both included.
1122334455
11, 22, 33, 44, 55, 66, 77, 88, 99.
It is 38.5, the number halfway between 33 and 44, which are the two middle numbers when they are listed in order.
11/13 = 22/26 = 33/39 = 44/52 = 55/65 . . .
11, 22, 33, 44, 55, 66, 77, 88, 99.
11, 22, 33, 44, and 55 are the first five multiples for eleven
11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 121
11, 22, 33, 44, 55.
11, 22, 33, 44, 55
11, 22, 33, 44, 55.
22-33-44-55-66
66
it is 11* 1=11 11*2=22 11*3=33 11*4=44 11*5=55 and 11*6=66
1122334455
11, 22, 33, 44, 55
They are: 11 22 33 44 and 55
11 22 33 44 55 66 77