Exactly 18 times
18
2.0*10^18
18
If you count 11 as 2 instances, the digit 1 appears 18 times if you don't count 10, 19 times if you do. 10,11,12,13,14,15,16,17,18,19,21,31,41,51,61,71,81,91
Exactly 10 times
Exactly 18 times
10 times as far as the Hyades's distance.
8 times
10 x 18 = 180
154 ÷ 18 = 8 remainder 10
180,000
4688
18 x 10
18
2.0*10^18
18