Interesting Math History

Question :
Where do the + and - signs come from ?

Answer :
The two symbols were used in the fifteenth century to show that boxes of merchandise were overweight or underweight. For overweight they used the sign + and for underweight the sign - . Within about 400 years accountants and mathematicians using them.
In the early 15th century the letters P and M were generally used for addition and subtraction in Europe.
The + symbol came from the Latin word et meaning and. The sign - may come from a shorthand version of the letter m itself.