Addition and subtraction within one hundred what are the techniques to calculate quickly in mind to seek ways.

Principles of quick calculation: more subtractions to be added; fewer subtractions to be subtracted; more additions to be subtracted; fewer additions to be added

Example: 48+95=48+100-5=148-5=143

Example: 92+13=92+10+3=102+3=105

Extended Information

Addition (usually represented by the plus sign "+") is one of the four basic operations of arithmetic, the rest being subtraction , multiplication and division.?

Addition has several important properties. It is interchangeable, which means that the order does not matter, and it is interrelated, which means that the order in which the addition is performed does not matter when more than two numbers are added. Repeatedly adding 1 is the same as counting; adding 0 does not change the result. Addition also follows related operations (such as subtraction and multiplication).

Addition is one of the simplest number tasks. The most basic addition: 1 + 1, can be counted by a five-month-old baby, or even by other animal species. In elementary education, students are taught to compute numbers on top of each other in the decimal system, starting with one-digit numbers and progressively solving more difficult number calculations.

Reference? Baidu Encyclopedia - Addition