1, rounding addition: rounding addition is a method of rounding addition, and the difference can be quickly calculated by adding it to the integer first. When 8+7= 15 is calculated, first add 8 to 108 and then add 2 to 107 and subtract 2 to be 5 10+5 = 17+9 = 26. For example, the calculation program is 17+3 = 2000.

2. Complement addition: Complement addition is fast, mainly because there is no trouble to carry it bit by bit. The complement is the sum of two numbers 10 100 1000 and so on. 8+2= 1078+22= 1008 is the complement of 2, 2 is the complement of 8, 78 is the complement of 22, and 22 is the complement of 78. The method of adding with complement is to add 1 to ten digits and subtract one digit.

Addition is a basic arithmetic operation, which combines more than two arrays into a number, and the result is called sum. Addition, subtraction, multiplication and division are collectively called "four operations". The symbol of addition is the plus sign "+". Connect items with a plus sign when adding. Add and after the equal sign "=".