All the math formulas in junior high school Junior 2

All the math formulas in junior high school Junior 2

Important and commonly used mathematical formulas from primary school to senior high school
Trigonometric function; logarithm; Adjunct
Fold a piece of rectangular paper. Given that angle one is equal to 30 degrees, how many degrees are angle two and angle three equal to, and how many degrees is angle two equal to?
Angle two and angle three are equal to 60 degrees and one is equal to 90 degrees. The sum of the inner angles of a triangle is 180 degrees. One angle of a rectangle is 90 degrees, and the other is 90 degrees minus 30 degrees, which is equal to 60 degrees
First of all, the unmarked corner adjacent to corner two on the left is an equal angle. The origami problem often involves "equal edge" and "equal angle".
From [horn 1 + horn 2 + the unmarked horn = 180 degree] formula: (let angle 2 be x degree)
2x+30=180
x=75
Jiao San··
Angle two, angle three, 75 degrees.
How do you discount it? Is it a triangle. If so, that's it.
180°-30°=150°
150°-90°=60°
A: angle one equals 90 degrees (or 60 degrees) and angle two equals 60 degrees (or 90 degrees).
Because there must be a right angle.
For example, the latitude and longitude 35 ° 50.163 'is converted into the formula of degrees, minutes and seconds
Take out 50 minutes and multiply 0.163 by 60 to get seconds. After conversion, it should be 35 ° 50'9.78 "
1. In a subtraction formula, the sum of the subtracted, the subtracted and the difference is 28, where the subtracted is 4.82 and the difference is ()
2. If there are two numbers a and B, the result of a plus B is 8, the result of a minus B is 1, and both a and B are decimals, then a and B are () and (), respectively
3. The decimal point of a is equal to B after moving one place to the right, the sum of a and B is 3.96, the number of a is (), and the number of B is ()
1, because the minuend = subtraction + difference, so the minuend + subtraction + difference = subtraction + difference + subtraction + difference = 2 (subtraction + difference) = 2 (4.82 + difference) = 28
So the difference is 9.18
2, a + B = 8,
A-B = 1, so a = B + 1 goes into the first equation
B + 1 + B = 8
B = 3.5
A = 4.5
3. By moving the decimal point of a to the right by one place, it is equal to B. we can see that B is ten times of A,
Because a + B = 3.96, so a + 10 a = 3.96
So a3.96 △ 11 = 0.36
B = 3.6
2. A: 4.5, B: 3.5
3. A: 0.36, B: 3.6
(1) -23.18
(2) A4.5 b3.5
(3) A 3.6 B 0.36
The difference is 9.18
A is 4.5, B is 3.5
36 for a and 3. 6 for B
nine point one eight
A4.5 b3.5
3.6 0.36
1. Poor: 9.18
2. A: 4.5 B: 3.5
3: A: 0.36 B: 3.6
1. Subtracted - subtracted = difference subtracted = subtracted + difference
Subtracted + subtracted + difference = 2 × subtracted
Subtracted = 28 △ 2 = 14
Difference = 14-4.82 = 9.18
2. A = (8 + 1) △ 2 = 4.5
B = (8-1) △ 2 = 3.5
3. If the decimal point is moved one place to the right, the number will be 10 times of the original, so B is 10 times of A
A = 3.96 ÷ (10 + 1) = 0.36
... unfold
1. Subtracted - subtracted = difference subtracted = subtracted + difference
Subtracted + subtracted + difference = 2 × subtracted
Subtracted = 28 △ 2 = 14
Difference = 14-4.82 = 9.18
2. A = (8 + 1) △ 2 = 4.5
B = (8-1) △ 2 = 3.5
3. If the decimal point is moved one place to the right, the number will be 10 times of the original, so B is 10 times of A
A = 3.96 ÷ (10 + 1) = 0.36
B = 3
How many degrees is 112 ° 20'42 ″!
112°20′42″
=112°20.7′
=112.345°
112.345 degrees
112。 345 Degrees
42÷60 = 0.7 ′
20.7÷60 = 0.345 °
So it's 112.345 degrees
There are 91 mangoes, peaches and papayas. The number of peaches is five times that of mangoes, and the number of papayas is seven times that of mangoes?
The age of the big tortoise this year is twice that of the little tortoise. Twenty years ago, the big tortoise was three times that of the little tortoise. Thirty years ago, the big tortoise was five times that of the little tortoise. How old are the big tortoise and the little tortoise?
3. The kindergarten aunt gives the children four chocolates each, and the remaining three chocolates, five chocolates each, but four chocolates are missing. Please calculate how many children are there? How many chocolates are there?
There is a clock that strikes six times at six. If it strikes six times in ten seconds, how many seconds does it take?
A bicycle has two wheels and a tricycle has three wheels. There are nine bicycles and tricycles in the shed. After counting, there are 24 wheels. Do you know how many bicycles and tricycles there are?
A snail needs to climb a 25 cm long bamboo pole. It takes 3 minutes to climb every 5 cm and 1 minute to rest. How long does it take for it to climb from the bottom to the top of the bamboo pole?
It must be understood by the second grade pupils
There are 91 mangoes, peaches and papayas. The number of peaches is five times that of mangoes, and the number of papayas is seven times that of mangoes?
91/（1+5+7）=7
Mango: 1x7 = 7
Peach: 5x7 = 35
Papaya: 7x7 = 49
The age of the big tortoise this year is twice that of the little tortoise. Twenty years ago, the big tortoise was three times that of the little tortoise. Thirty years ago, the big tortoise was five times that of the little tortoise. How old are the big tortoise and the little tortoise?
20 / (5-3) = 10 (years old)
Little Turtle: 10x4 = 40 (years old)
Big tortoise; 40x2 = 80 years old
3. The kindergarten aunt gives the children four chocolates each, and the remaining three chocolates, five chocolates each, but four chocolates are missing. Please calculate how many children are there? How many chocolates are there?
Number of people: (3 + 4) / (5-4) = 7 (people)
Chocolate number: 4x7 + 3 = 31
There is a clock that strikes six times at six. If it strikes six times in ten seconds, how many seconds does it take?
Knock 6, there are 5 intervals, each interval: 10 / 5 = 2 (seconds)
10 knocks, 9 intervals: used: 9x2 = 18 (seconds)
A bicycle has two wheels and a tricycle has three wheels. There are nine bicycles and tricycles in the shed. After counting, there are 24 wheels. Do you know how many bicycles and tricycles there are?
Suppose that each vehicle has 2 wheels removed, then 2x9 = 18 wheels are removed,
There are 24-18 = 6 (pieces) left, which is the rest of tricycles. Each tricycle has one wheel left,
Six wheels have six tricycles, bicycles have: 9-6 = 3
A snail needs to climb a 25 cm long bamboo pole. It takes 3 minutes to climb every 5 cm and 1 minute to rest. How long does it take for it to climb from the bottom to the top of the bamboo pole?
25/5=5
3x5 = 15 (min)
1x4 = 4 (min)
15 + 4 = 19 (points)
1. If mango is x, then peach is 5x, papaya is 7x, and the total is 13X, then there are 7 mangoes, 35 peaches and 49 papaya,
1 Let X be the number of mangoes, then the number of peaches is 5x and the number of papaya is 7x.
X + 5x + 7x = 91 get X
2 if the age of this year's little turtle is x, then the age of this year's big turtle is 2x.
Twenty years ago, the age of the Little Turtle was x-20, and that of the big turtle was 2x-20
(x-20) * 3 = 2x-20
Find out X
Three children.
4X + 3 = 5x-4
To solve x, you can find the number of children on the left or right of the equation and get education / Science > learning help to add to the collection to be solved
Report the math problems of grade two in primary school, please help to solve them (a total of 6 problems, please explain in detail)
Reward points: 20 - 14 days and 23 hours to the end of the problem
There are 91 mangoes, peaches and papayas. The number of peaches is five times that of mangoes, and the number of papayas is seven times that of mangoes. Mango, peach, papaya how many each?
The age of the big turtle this year is twice that of the little one; 20 years ago, the big turtle was three times that of the little one; 30 years ago, the big turtle was five times that of the little one. How old are the big tortoise and the little tortoise?
3. The kindergarten aunt gave the children 4 chocolates each, the remaining 3 chocolates, 5 chocolates each, and 4 chocolates were missing. How many children are there, please? How many chocolates are there?
There is a clock that strikes six at six. If it takes 10 seconds for six knocks, think about it. How many seconds does it take for 10 knocks?
A bicycle has two wheels and a tricycle has three wheels. There are nine bicycles and tricycles in the shed. After counting, there are 24 wheels. Do you know how many bicycles and tricycles there are?
A snail needs to climb a 25 cm long bamboo pole. It takes 3 minutes to climb every 5 cm and 1 minute to rest. How long does it take for it to climb from the bottom to the top of the bamboo pole?
The second grade students must be able to understand
Questioner: qing19770905 - level 2
Let me answer:
5 + 7 + 1 = 13 (portion) 91 except 13 = 7 (piece) peach: 7 × 5 = 35 (piece) papaya: 7 × 7 = 49 (piece)
Mango: 7 × 1 = 7
A: 35 peaches, 49 papayas and 7 mangoes.
2 + 3 + 5 = 10 (pieces) 20 + 30 = 50 (years) 50 divided by 10 = 5 (Times) 20 divided by 5 = 4 (years) 30 divided by 5 = 6 (years)
4 + 6 = 10 (years old) 10 + 50 = 60 (years old) 60 × 2 = 120 (years old)
A: the little turtle is 60 years old and the big turtle is 120 years old.
3 × 4-3 = 9 (grains) 5 × 4 + 4 = 24 (grains) 24-9 = 13 (persons) 13 × 4 + 3 = 55 (grains)
A: there are 13 children, 55 chocolates.
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Anonymous answer points rule
There are 4 answers
Prosecution 1.7 35 49
2.80 40
3.7 31
4.100/6
5.3 6
six point one nine
Responder: halo dance paradise - level 4 12:36, December 3, 2009
In question 1, suppose mango is x, then peach is 5x, papaya is 7x, and the total is 13X. The solution is 7 mangoes, 35 peaches and 49 papaya,
Respondent: 123456lxdwan - level I 2009-12-3 12:39
Prosecution 1: if the number of mangoes is x, then the number of peaches is 5x and the number of papaya is 7x.
X + 5x + 7x = 91 get X
2 if the age of this year's little turtle is x, then the age of this year's big turtle is 2x.
Twenty years ago, the age of the Little Turtle was x-20, and that of the big turtle was 2x-20
(x-20) * 3 = 2x-20
Find out X
Three children.
4X + 3 = 5x-4
Solution x, the number of children can be found on the left or right side of the equation
4. 10 seconds for 6 knocks, then 10 divided by 6 seconds for 10 knocks, 10 times 10 divided by 6
5. If there are x self-study cars, there are (24-2x) / 3 tricycles.
X + (24-2x) / 3 = 9
6. Set the time for X minutes
X/4*5=25
Respondent: bjxiny - level 2 2009-12-3 12:51
There are 91 mango, peach and papaya reported. The number of known peaches is five times that of mango and papaya is seven times that of mango. Mango, peach, papaya how many each?
91/（1+5+7）=7
Mango: 1x7 = 7
Peach: 5x7 = 35
Papaya: 7x7 = 49
The age of the big turtle this year is twice that of the little one; 20 years ago, the big turtle was three times that of the little one; 30 years ago, the big turtle was five times that of the little one. How old are the big tortoise and the little tortoise?
20 / (5-3) = 10 (years old)
Little Turtle: 10x4 = 40 (years old)
Big tortoise; 40x2 = 80 years old
3. The kindergarten aunt gave the children 4 chocolates each, the remaining 3 chocolates, 5 chocolates each, and 4 chocolates were missing. How many children are there, please? How many chocolates are there?
Number of people: (3 + 4) / (5-4) = 7 (people)
Chocolate number: 4x7 + 3 = 31
There is a clock that strikes six at six. If it