Difference is a mathematical operation, especially the result of subtracting two numbers. Sum refers to a new thing obtained by adding two or more things with the same nature, and can also be narrowly understood as the result of adding two numbers. Generation of sum: addend+addend = sum.

Subtraction is one of the four operations, and the operation of subtracting one number from another is called subtraction; Given the sum of two addends and one of them, the operation of finding the other addend is called subtraction. The symbol of subtraction is "-",which is pronounced as negative sign. Addition is one of the four basic operations, which refers to the calculation of combining two or more numbers and quantities into one number and quantity. The symbol of addition is the plus sign "+". Connect items with a plus sign when adding.