Mathematics has always been an important subject in primary school, and laying a good foundation for mathematics is also conducive to children's subsequent study and growth. I always hear parents say that children in primary schools are always confused about the laws of mathematics and are prone to arrogance.

Today, I will bring you this "27 Rules of Primary Mathematics" to help children remember the rules of mathematics. It can be used to help children do their homework.

Write the addition of two numbers, and remember that three 1 numbers are aligned; 2. Starting from the unit; 3. When the number of digits reaches 10, enter 1 into ten digits.

Align the same numbers; Reduce from the unit; If the number of digits is not enough, retreat from ten digits; Unit plus 10, then subtract.

In the formula without brackets, only addition and subtraction or only multiplication and division are done in turn from left to right; In the formula without brackets, if there are multiplication and division and addition and subtraction, the multiplication and division should be calculated first, and then the addition and subtraction should be calculated; If there are parentheses in the formula, count the parentheses first.

Read in order from the top, from thousands to hundreds, and so on; There is a zero or two zeros in the middle, and only one "zero" is read; No matter how many zeros there are, don't read the last one.

Write in order from the high position; Write a few words on thousands, write a few words on hundreds, and so on. Write "0" in the middle or at the end. Align the same numbers; Reduce from the unit; Which digit is not reduced enough is to add 1 from the previous digit and 10 to the standard and then reduce it.

Starting from the unit, multiply each digit in multiple digits by one digit in turn; Whoever has the highest score will advance several times. Starting from the high-order divisibility of the dividend, try to divide the first digit of the dividend by the divisor every time. If it is less than the divisor, try to divide the first two digits. Write the quotient where the divisor is divided;

For each quotient, the remainder must be less than the divisor. First, multiply the number on two digits by another factor to get that the last digit of the number is aligned with the two digits; Then multiply the number on the tenth digit of the two-digit number by another factor to get that the last digit of the number is aligned with the tenth digit of the two-digit number;

Then add up the numbers multiplied twice. Try to divide the first two digits of the dividend by the divisor of the high order of the dividend. If it is less than the dividend, try to divide it by the first three digits of the dividend. Write the business on the one except the bonus; For each quotient, the remainder must be less than the divisor.

Read Level 10,000 first, then Level 1; Ten thousand series should be read according to the pronunciation of the first level, and then add a word "ten thousand" at the back; No matter how many zeros there are in the last digit of each level, other numbers have one or several zeros, and there is only one "zero" in a row.