A set of mathematical formulas used by second-year students
1. If facing east, the back is west, the left is north, and the right is south. If facing west, the back is east, the left is south and the right is north.
If you face south, your back is north, your left is east and your right is west.
2, 1 =60 minutes, 1 minute =60 seconds.
3. Elapsed Time = End Time-Start Time
Start Time = End Time-Elapsed Time
End Time = Start Time+Elapsed Time
4. Common time units are sometimes minutes and seconds.
5. There are 12 big squares and 60 small squares on the clock. It takes 1 hour to walk a big square in an hour hand, 1 minute to walk a Little Square in a minute hand and 5 minutes to walk a big square in a minute hand.
6. In the division formula with remainder, the remainder must be less than the divisor.
7. According to the relationship between the parts of division, the following formula can be derived:
Dividend = Divider× Quotient+Remainder
Divider = (Divider-Remainder) ÷ Quotient
Quotient = (dividend-remainder) divider
Remainder = dividend divided by quotient
8. There are addition, subtraction, multiplication and division in the formula without brackets. Multiply and divide first, then add and subtract. If there is only addition and subtraction or only multiplication and division, it should be calculated from left to right. Formulas in brackets should be calculated first.
9. By all directions, we usually mean "east, west, south, north, southeast, northeast, southwest and northwest".
10, 10 One thousand is ten thousand; 10 One hundred is one thousand; 10 Ten is one hundred. 2 1. From the right, the first place is the unit, the second place is ten, the third place is one hundred, the fourth place is one thousand, and the fifth place is ten thousand.
The second part of the encyclopedia of mathematical formulas for second-year students
1, two meanings of multiplication: (1) means: how many sums are equal.
(2) Indicate: What is the sum of several?
2. Three meanings of division:
(1) means: divide a number into several parts on average, and each part is several parts. (the meaning of sharing equally)
(2) indicates that there are several numbers in a number. (including the meaning of division)
(3) indicates that one number is several times that of another. (the meaning of multiple division)
Find out how many times one number is another number, and then divide it.
4. Know that one number is several times that of another number, and find a number by multiplication.
5. Know that one number is several times that of another number, and find another number by division.
6. Find the multiple of a number by multiplication.
7. Equitable formula: total number ÷ number of copies = number of copies.
8. Formula including division: total number ÷ each copy = number of copies.
9. Be familiar with the names of all parts of multiplication and division and the reading of formulas.
3×4= 12
Multiplier product? (Reading: 3 times 4 equals 12. )
12÷4=3
Divider divisor quotient? (Reading: 12 divided by 4 equals 3. )
10, on the map, it is generally up north, down south, left west, right east.
A set of mathematical formulas used by second-year students
1, note when reading: No matter how many zeros are at the end, there is one or more zeros in the middle, and only one zero is read. Note when writing numbers: there is nothing on any number, just fill in a zero placeholder on that number. 2, compare the size of the quantity should pay attention to:
(1) The number with more digits is greater than the number with fewer digits;
(2) When the number of digits is the same, the number of digits is greater than that of digits; When the number of digits is the same, it will go down in turn. The ratio of one digit to another digit, which digit is larger, indicates that the number is larger.
3. When reading, read from (), in the order of (from high to low).
4. Length units: kilometers, meters, decimeters, centimeters and millimeters.
Expressed in letters: km, m, dm, cm, mm.
5. The forward speed between the commonly used "adjacent" length units is "10", the forward speed between the "separated" 1 00 "and the forward speed between the two" separated "length units is" 1000 ". We also derived seven unit conversion formulas, namely:
1m = 10 decimeter 1m= 10dm
1 decimeter =10cm1DM =10cm.
1cm = 10mm 1cm = 10mm
1m = 100cm 1m = 100cm
1 decimeter = 100 mm 1dm = 100 mm
1m = 1000mm 1m = 1000mm
1 km = 1 000m1km =1000m
6. We also know that there are (10) cells in 1cm, and the length of each cell is1mm.
1 decimeter is about the length of a palm. 1 cent coins are about 1 mm thick. When long distance is expressed, it is expressed in "kilometers".
7. Written calculation method of three-digit addition (carry addition):
(1) The same number is aligned;
(2) Starting from the unit;
(3) Whoever reaches 10 will be promoted to 1.
8, three-digit subtraction (abdication subtraction) written calculation method:
(1) The same number is aligned;
(2) from the unit;
(3) If the reduction is not enough, borrow a 1, and then add this 10 to reduce it.
9. When estimating in this unit, the number can be regarded as an integer or an integer, so that the estimated answer will be closer to the actual answer.
10. We can check whether the result is right or wrong.