To sum more than two numbers quickly, follow these easy steps:

1. Don't sum the numbers pairwise.
2. Stack the numbers vertically, and align them to the right.
3. Compute the sum of each column of digits, starting from the right.
4. Proceed until you reach the last digit of the longest number.

That's it!

Historians speculate that the symbol + came to represent the addition as the result of a lengthy modification of the Latin conjunction et. The introduction of the symbol + for addition is relatively recent, dating back to the 14th century. Before that, different symbols were used, including p̅ and the bidirectional glyph used by Egyptians.

Addition and difference are substantially the same mathematical operation. However, for positive numbers:

• The result of addition is always larger than both factors; and
• The result of subtraction is always smaller than at least one of the numbers.

Introducing negative numbers in math allows generalizing the sum to a single operation, the algebraic sum.