Simple operation of 4.3 minus 4.3 times 0.9

Simple operation of 4.3 minus 4.3 times 0.9

4.3 minus 4.3 times 0.9
=4.3x(1-0.9)
=4.3x0.1
=0.43

1 / 4 in addition to brackets 3-13 in 5-13 in 8 brackets is equal to how much better there is a calculation process

1/4÷(3-5/13-8/13)
=1/4÷[3-(5/13+8/13)]
=1/4÷(3-1)
=1/4÷2
=1/4×1/2
=1/8

Number reasoning: 1, 22, 36, 40, 56, 68, 2, 67, 54, 46, 35, 29, 3, 2187729, 81, 3,

1、 22, 36, 40, 56, 68, etc. from the sequence of numbers, ten digits are equal difference numbers, so it is deduced that the tens of digits are 7, and the single digits seem to be irregular. But if you look closely at the sum of the smallest and largest single digits, you will get 8, and the sum of the second smallest and the second largest is also 8. Therefore, it is reasonable to deduce that the number of digits is 2, and the solution is 72, Second, we can see 67 = (54 + 46-35) + 2, 54 = (46 + 35-29) + 2. From this, we can boldly deduce 46 = (35 + 29 -) + 2, so the solution is 20. Third, we can see 2187 = 729 × 3, 729 = 81 × 3, 81 = 3 × 3, so 3 =? × 3 ^ 4, so the solution is 3 / 81

How about 2 / 9 minus 5 / 8 times 2 / 9

2/9-5/8×2/9
=2/9×（1-5/8）
=2/9×3/8
=1/12

76 △ 6 + 20 × 1 / 6 + 1 / 6 is calculated by a simple method

76 △ 6 + 20 × 1 / 6 + 1 / 6 = 1 / 6 (76 + 20 + 1) = 1 / 6 × 97 = 97 / 6

On the two real roots of the equation x & # 178; - (2m + 1) x + M-8 = 0 of X, one is greater than - 1 and the other is less than - 1, the range of M is obtained

F (x) = x & # 178; - (2m + 1) x + M-8 opening upward
One of the two real roots of X & # 178; - (2m + 1) x + M-8 = 0 is greater than - 1 and the other is less than - 1
Then f (- 1) < 0
1+(2m+1)+m-8＜0
1+2m+1+m-8＜0
3(m-2)＜0
m＜2

Calculation: what is the quotient of 2 times (- 5) product minus 48 divided by (- 12 + 4)?
emergency

2*(-5)-48/(-12+4)
=-10-48/(-8)
=-10+6
=-4

A rectangular wooden box is 2 meters long, 52 cm wide and 82 cm high. The board thickness of the box is 1 cm. Do you know the volume of the box?
Give the formula and the reason for doing so (preferably distributed)

Rectangular wooden box (with cover plate)
Inner box length = 2m-2cm = 200cm-2cm = 188CM
Inner box width = 52 cm - 2 cm = 50 cm
Inner box height = 82 cm - 2 cm = 80 cm
Volume of wooden box = 188 * 50 * 80 = 752000 cubic centimeter = 0.752 cubic meter
Cuboid wooden box (without cover plate)
Inner box length = 2m-2cm = 200cm-2cm = 188CM
Inner box width = 52 cm - 2 cm = 50 cm
Inner box height = 82cm - 1cm = 81cm
Volume of wooden box = 188 * 50 * 81 = 761400 cubic centimeter = 0.7614 cubic meter

In terms of scientific creation, we can cite the age when some famous people in history achieved achievements: Galileo discovered the pendulum principle at the age of 17,
Newton founded calculus at the age of 20?

Young people tend to be more active than young people. They can find more interesting scientific phenomena in their lives. Young people's scientific achievements are more profound
The best age for scientific creation is youth

Let the sum of n items of a sequence of positive numbers be Sn, satisfying 4sn = 4 (an + 1) ^ 2-4n-1, n belongs to positive integer, and A2, A5 and A14 constitute an equal ratio sequence
(1) To prove a 2 = root sign (4a 1 + 5) (here is a 2 A2 or a 2 T T T, I prove a 2 A2) (2) to find the general term formula of sequence an, don't copy it. It's different from the problem on the Internet

Solution: (1) because 4A1 = 4a2 ^ 2-4-1, so 4A1 = 4a2 ^ 2-4-1, so A2 = (4A1 + 5) / 2; (2) because 4sn = 4 (an + 1) ^ 2-4n-1, and S1 = A1, so 4A1 = 4a2 ^ 2-4-4-1, so A2 = (4A1 + 5) / 2; (2) because 4sn = 4 (an + 10) ^ 2-4n-1, so 4S (n-1) = 4An ^ 2-2-4 (n-2-4 (n-4 (n-1) - 4 (n-4 (n-1) because 4sn-s (n-1) = an, so 4A1, so 4A1, so 4 (an + 1) ^ 2-4n-2-4n-4n-4n-4n-2-4n-4n-1 - [4An ^ 2-4n-1 - [4An ^ 2-4 (4An ^ 2-2-2-4 (n ^ 4 into a series of equal proportions