Answer:

This part of the extended information mainly examines the knowledge points of subtraction:

Represents an operation to remove an object from a collection. Its symbol is the minus sign (? )。 For example, in the picture on the right, there are five? Two apples, five apples, two were taken away, leaving three apples. So 5? 2 = 3。 Subtraction is to remove or reduce physical quantities and abstract quantities with different objects (including negative numbers, fractions, irrational numbers, vectors, decimals, functions and matrices).

Subtraction follows several important patterns. It is anti-commutative, which means that changing the order will change the sign of the answer. It is not associative law, that is, when a subtraction exceeds two numbers, the order of subtraction is very important.

Subtracting 0 does not change a number. Subtraction also follows predictable rules related to addition and multiplication. These laws can be proved, starting with the subtraction of integers and summarizing them with real numbers and other things. Continue the general binary operation of these patterns and learn in abstract algebra.