How many possibilities are there if a two digit number plus a two digit number equals 43? Why? If: □ - □ = 43 two digit minus two digit equals 43, how many possibilities are there? Please explain why?

How many possibilities are there if a two digit number plus a two digit number equals 43? Why? If: □ - □ = 43 two digit minus two digit equals 43, how many possibilities are there? Please explain why?

The smallest two digits are 10,
10 + 33 = 43, then 11 + 32, 12 + 31... Until
21 + 22 = 43, then repeated, so there are 12 species
Similarly, the second question starts with the smallest two digit 10, and 10 is subtracted,
53-10 = 43, then 54-11, 55-12,... Until the subtracted reaches the maximum two digit 99, that is
99-56 = 43, so there are 47 species

Five out of six minus a score, and four out of nine plus the same score, they get the same number. What's the score?
We need formulas, not equations

1. The score = (5 / 6-4 / 9) △ 2 = 7 / 36

Is one cubic meter of water equal to one ton of water?

Yes

On the quadratic equation of two variables
Xiao Ming is walking on the road. He finds that every six minutes there is a bus coming from behind, and every two minutes there is a bus coming from the front,

Let a car leave the station in X minutes at a speed of a and a speed of B
Six minutes when a car comes from behind can be regarded as chase problem, two minutes when a car comes from front can be regarded as encounter problem
6（a-b）=ax
2（a+b）=ax
The solution is x = 3
It will be sent every 3 minutes

Regular formula of 1,6,18,36,60,90 general term formula of 9,11,15,21,29,31 general term formula of 11,15,21,29,39

The regular formula of 1,6,18,36,60,90: A1 = 1, an = 3N (n-1) n = 2,3,4... 9,11,15,21,29,31: an = n (n-1) + 9, n = 1,2,3,4,5, AK = a (K-4) + 20

（1+3+5+*****+99）-（2+4+8+****+100）=（）

=(1-2)+(3-4+.).+(99-100)=-50

A coin collector wants to change 3.50 yuan notes into 1, 2 and 5 cents coins. He requires that the total number of coins should be 150, and each coin should be no less than 20. 5 cents should be more than 2 cents. Please design the exchange scheme accordingly

Let x, y and Z coins be exchanged for 1, 2 and 5 cents respectively, then x + y + Z = 150x + 2Y + 5Z = 350y < ZX ≥ 20, y ≥ 20 and Z ≥ 20. From (1) and (2) we get x = 3Z − 50y = 200 − 4Z, and substitute X and Y into (3) and (4) we get: 3Z − 50 ≥ 20200 − 4Z ≥ 20Z > 200 − 4Z, and the solution is: 40 < Z ≤ 45, then z = 41, 42, 43, 44 and 45, from which we get the corresponding values of X and y, and then we get five schemes (x, y) ，y，z）=（73，36，41）；（x，y，z）=（76，32，42）；（x，y，z）=（79，28，43）；（x，y，z）=（82，24，44）；（x，y，z）=（85，20，45）．

How many feet is 58.4 cm

1.752 feet (3 feet equals 1 meter)

Feel the nature,

Feeling the nature, I walk alone with light steps, with a good mood, gently, close to the nature. Look around, the forest is a thick green, green elegant, quiet. This green, quietly stirred my heartstrings. Walking forward, a spring like sound, attracted my heart in the past. Eh, it stopped in the ginseng

How to write the magic clone reading?

(1) Because each cell has the same gene, the shape of each cell controlled by gene is the same
(2) As a kind of somatic cell, mammary gland cell has lost its totipotency
(3) Artificial manufacturing
(4) Farming, animal husbandry and medicine