The arithmetic number column is one kind of common number column, starting from the second term, each term and its previous term difference be tantamount to the same constant number, The number column is called the arithmetic number column, and the constant number is called the arithmetic number column tolerance, and the tolerance is often expressed in letter d. Example: 1,3,5,7,9...... 1+2(n-1).

Arithmetic number column general term formulas is: an=a1+(n-1)d (1) First n term and formulas is: or Sn=n(a1+an)/2. Note: The above n is an integer number.