Addition Column is a mathematical concept that involves the addition of numbers in columns. ONES, Tens, and Tenths are three terms used to describe the columns in an Addition Column. ONES refers to the column of numbers on the right side of the equation, which are the ONES place values. Tens refers to the column of numbers in the middle of the equation, which are the tens place values. Tenths refers to the column of numbers on the left side of the equation, which are the tenths place values.