Use positive and negative numbers to record the use of Chinese New Year red envelopes.

Record the weather in the last week with the knowledge of positive and negative numbers;

1, how many degrees Celsius is a positive "zero"; How many degrees Celsius is the minus of a negative number. For example, "-3℃ means minus 3℃, and 2℃ means minus 2℃.

2. Use positive and negative numbers to indicate the difference from the average temperature. Positive numbers represent degrees above the average temperature; Negative numbers represent degrees below average temperature. For example, the weather in the last week (average temperature 18℃). It is represented by the knowledge of positive numbers and negative numbers, as shown below: "-3 degrees Celsius" means 3 degrees Celsius lower than the average temperature, and "2 degrees Celsius" means 2 degrees Celsius higher than the average temperature.

Extended data:

In decimal numbers, you can add "+"and "-"before the number to indicate positive and negative numbers. Obviously, digital circuits cannot directly recognize the "+"and "-"symbols. Therefore, in digital circuits, the most significant bit of a number is used as the sign bit, and 0 is used to represent the "+"sign. The "-"sign is represented by 1, and its symbol is digitized into such a binary number called the machine number. Numbers with "+"and "-"are called true values.

According to different needs, there are three representations of negative numbers in the phone number: original code, complement and complement.

1, original code

The original code is also called "sign-amplitude code", and its mantissa part represents the absolute value (i.e. amplitude) of the number, and the sign bit represents the sign of the number, representing positive and negative numbers, for example, x=0.0 1 1, representing +0.375, and x = 1.065438.

Step 2 supplement

Complement is also called "two's complement". The positive number in the complement is the same as that in the original code. The negative number in the complement is represented by the complement of 2, that is, the negative number is added with 2 first. In order to convert the addition of positive and negative numbers into the addition of positive and negative numbers, the difficulty of addition and subtraction in the original code representation is overcome.

3. Anti-code

The complement is also called the complement of 1. Like complement, the positive number of the reverse code is the same as the positive number of the original code. The negative number of the complement is to change the positive representation of the number from 0 to 1, 1 to 0, that is, "negation". For example, x=-0.375, and its positive expression is: 0.0 1 1. If we reverse all of its 0. 1, we get 1. 100, which is the representation of x=0.375.