Playing bamboo boards rang all over the sky. Listen to me, students Today we will talk about four operations instead of other tables. Clear order is the key to calculating mixed questions.

The operation at the same level is the best, and it is calculated from left to right in turn. Two levels of operations appear, first multiply and divide and then add and subtract. What should I do if I encounter parentheses? Count the parentheses first, then the parentheses. The order must not be out of order. Every step is checked, which is both right and happy.

Primary school mathematics knowledge jingle:

1. Year, Month and Day:

135780 wax (65438+February), 3 1 day never goes bad; April 30th (165438+1October); February 28th in normal year, plus February 1 day in leap year.

2. prime formula within 100:

2,3,5,7 and 1 1, 13 are followed by 17.

19, 23, 29, ( 19, 23, 29).

3 1, 37,41,(Sany, Sanqi, Forty-one).

43, 47, 53, (43, 47, 53).

59, 6 1, 67, (59, 6 1, 67).

7 1, 73,79, (73,79 July 1 day).

83, 89 and 97, (83, 89 and 97).

Third, multi-digit reading of French songs:

Reading should start from a high position, and whoever reads it several times will read it several times. If there is a zero at the end of each level, you don't need to read it in your mind. If other numbers are zero in a row, read one, read ten thousand at the end of ten thousand, and read one hundred million at the end of one hundred million.

Fourth, multi-digit song writing:

Write numbers from high places, write as many as possible, remember which position has no units, and use 0 to occupy the position.

Five, multi-digit size comparison Song:

The number of digits is different from the size, with more digits, less digits and the same digits.