10

Keep practicing — related questions

• 100 : 102 :: 100000 : ?
• 1,2,3,10,?
• XX
• 10, 11, 101, 111, 1011...
• 10
• 1, 4, 9, 25, 49, ----
• 11025
• 1, 9, 25, 49, X, 121