Formula calculation 1. The number of girls in grade five accounts for four ninth of the total number of students in grade five, one fourth of the total number of students in grade five, and what percentage of the total number of students in grade five? 2. In a subtraction formula, if the subtraction is equal to four ninths of the subtracted, what is the difference equivalent to? 3. Three quarters of the number a is equal to two thirds of the number B. A: how much is the number B? 4. For a simplest fraction, if the numerator adds 1, the fraction becomes 1; if the numerator subtracts 2, it can be reduced to two-thirds. What is the simplest fraction?

Formula calculation 1. The number of girls in grade five accounts for four ninth of the total number of students in grade five, one fourth of the total number of students in grade five, and what percentage of the total number of students in grade five? 2. In a subtraction formula, if the subtraction is equal to four ninths of the subtracted, what is the difference equivalent to? 3. Three quarters of the number a is equal to two thirds of the number B. A: how much is the number B? 4. For a simplest fraction, if the numerator adds 1, the fraction becomes 1; if the numerator subtracts 2, it can be reduced to two-thirds. What is the simplest fraction?

How to arrange the questions, answers, formulas, checking and calculation

Examination > formulation > calculation > checking calculation > answer

Finding the maximum value of function f (x) = x - (1 / x) on [1,3]

F (x) monotonically increasing
So f (x) min = f (1) = 0
f(x)max=f(3)=8/3

Practice of finding rules in primary school
25.10.4. (). (). Regular. What are the last two?

1.60.64 (the rule is that the number before is divided by 2.5 to get the number after)

Is 0 a natural number?
the sooner the better

Historically, there are two opinions about whether 0 is a natural number: one is that 0 is a natural number, the other is that 0 is not a natural number. Since the founding of the people's Republic of China, the textbooks of primary and secondary schools in China have stipulated that natural number does not include 0

On the univariate linear equation of X: kx-x-m = (2k-1) x + 4

On the left is (k-1) x-m,
If both sides subtract (k-1) x at the same time, then KX = - M-4,
If k = 0,
If - M - 4 = 0, then x can be any number
If - M-4 ≠ 0, then x has no solution
If K ≠ 0,
X = （-M-4)/K,

Find some problems in primary school mathematics homework in Volume 2 of grade 5. Let me do them

1、 The law of number arrangement
1. 4, 10, 16, 22, 28, find the nth digit ()
2. 2, 3, 5, 9, 17, the increase is 1, 2, 4, 8
3. Observe the following formula numbers: 0, 3, 8, 15, 24, & ﹥ 8222; & ﹥ 8222;. Try to write the 100th number and the nth number according to this rule
4. Item n of 1,9,25,49, (), (), is (),
5: 2, 9, 28, 65: the nth digit ()
6: 2, 4, 8, 16. The nth digit
7: 2, 5, 10, 17, 26, the nth digit
8: 4,16,36,64,?, 144196, &? The hundredth number ()
9. Look at the next two lines
2,4,8,16,32,64, ．．．（1） 5,7,11,19,35,67．．．（2）
According to the rule you found, take the tenth number in each row and get their sum
10. White black black black black black black black black black black black black black white black black black black black black black black black black black black black black black black black black black white black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black black
How many are black?
11. 12,20,30,42,( ) 127,112,97,82,( ) 3,4,7,12,( ),28
12. 1,2,3,5,( ),13
13. 0,1,1,2,4,7,13,( )
14. .5,3,2,1,1,( )
15. 1,4,9,16,25,( ),49
16. 66,83,102,123,( ) ,
17． 1,8,27,( ),125
18. 3,10,29,( ),127
19, 0,1,2,9,( )

Write 3 natural numbers at random. Try to show that the sum of two numbers is even

Classification:
1. If all three natural numbers are even, the sum of the two numbers must be even;
2. If two of the three natural numbers are even, the sum of the two even numbers is even;
3. If only one of the three natural numbers is even, the sum of the two odd numbers is even
So if you write three natural numbers, the sum of two numbers is even

The sixth root of (- 2) ^ 2

The sixth root of (- 2) ^ 2
=The sixth power root of 2 & #
=³√2

There is a batch of goods in the warehouse. The weight ratio of the goods transported away and the remaining goods is 2:7. If 64 tons are transported away, the remaining goods are only 3 / 5 of the original warehouse
How many tons of the original goods in the warehouse

64 / [1-3 / 5-2 / (2 + 7)] = 64 / [8 / 45] = 360 tons