Riddle

My numbers may vary, thin as a sheet, take one away, and we're just not complete. What am I?

Choose an answer

A.A calendar
B.A deck of cards
C.A notepad
D.A Book.
Hint: It's a 2-word phrase with 5 letters, starting with "A".

Answer

A Book.

Why this is the answer

A book's pages are thin sheets numbered in sequence, and removing one leaves it incomplete.

This riddle is filed under How, What, Why Riddles and rated Medium.