Numbers are the addition and subtraction of 6 and 7.

The formulas for addition and subtraction of numbers 6 and 7 are as follows:

First, the number is 6 plus or minus.

1+5=6,5+ 1=6;

2+4=6,4+2=6;

3+3=6;

7- 1=6; 8-2=6; 9-3=6。

Second, the number is the addition and subtraction of 7.

1+6=7,6+ 1=7;

2+5=7,5+2=7;

3+4=7,4+3=7;

8- 1=7; 9-2=7; 10-3=7。

Three. Definitions of 6 and 7

"Addition and subtraction of 6 and 7" is the content of the first book of primary school mathematics published by People's Education Press. The main content is the addition and subtraction of 6 and 7, which is based on the addition and subtraction within 5.

"6" is a positive integer and composite number of Arabic numerals, natural numbers, rational numbers and natural numbers between 5 and 7, and it is one of the ten numbers composed of natural numbers.

Equivalent to the Chinese word "Liu" or "Lu" (meaning several times), it symbolizes harmony, auspiciousness, care and nurturing in China and is highly valued in traditional culture, such as "Liu Liu Dashun". At the same time, 6 is the cosmic number of the material world, so the Egyptians chose this number to represent time and space.

"7" is an Arabic numeral and a green natural number between 6 and 8. It is the fourth prime number and one of the odd numbers, which is equivalent to "seven" or "seven" in Chinese characters.

The concept and law of addition and subtraction;

1, the definition of addition and subtraction

(1) addition: The operation of combining two numbers into one number is called addition.

A+b=c, A is called addend, B is also called addend, and A+B = C is called sum.

(2) subtraction: the operation of finding another addend by knowing the sum of two numbers and one of them is called subtraction.

A-b=c, a is called minuend, b is called subtraction, and A-B = C is called difference.

0 can do addend and subtraction, but not minuend (primary school).

2, the size of the law

Add any number to 0, and the sum equals the original number; The sum of two numbers that are not 0 must be greater than one of the addends.

3, the size of the difference.

Any number MINUS 0, the difference is equal to the original number; When two numbers that are not 0 are subtracted, the difference must be less than the minuend; When two equal numbers are subtracted, the difference must be equal to 0.