According to the law of numbers, what number should be filled in the question mark

According to the law of numbers, what number should be filled in the question mark

Rule: the difference between the sum of the top three numbers and the sum of the bottom two numbers is equal to the number in the middle
（1）（2+4+7）-（3+1）=9
（2）（3+3+5）-（4+2）=5
So? = (6 + 9 + 2) - (4 + 3) = 10

What mathematical rules can you find in the M-matrix of calendar chart
One two three four five six
1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30
3 5
10 11 12
17 19
What number rules can you find in this M-matrix? Please help!

If it is Monday, the calendar is calculated as:
The first: 1 + 7-1 = 7
Week 2: 1 + 14-1 = 13
Week 3: 1 + 21-1 = 21
Week 4: 1 + 28-1 = 28
If it is a Wednesday, it is calculated as:
3+7-1=9
3+14-1=16
3+21-1=23
3+28-1=30
That is to say, the day of the week plus the number of times of the week * 2 and minus 1 will be the date of the month

How to make a matrix graph

You can determine a unique rule by yourself, and follow it to arrange the numbers horizontally or vertically. Of course, you can also design your own unique patterns. The charm of digital array is that it contains imperceptible rules and beautiful mini lineup!

As shown in the figure, 1, 2, 3... Form a number matrix to observe the law
one
2 3
6 5 4
7 8 9 10
15 14 13 12 11
.
Find the minimum number in the nth row

Observation is available
Number of rows n minimum x
1 1
2 1+1=2
3 1+1+2=4
4 1+1+2+3=7
5 1+1+2+3+4=11
..
X = 1 + (the square of N-N) / 2 is obtained by mathematical induction and summation formula of arithmetic sequence