The following is a regular array of triangles (1). If you look at the array carefully, what rules do you find? The first line: 1 the second line 1 the third line one 1 1 1 2 1 1 3 3 1 1 4 6 4 1 1 5 10 10 5 1

The number below is the sum of the two numbers above

What's the problem?
1 8 25 ? 125
Excuse me? What is it
Let's talk about the train of thought
What about 25125

1 is 1 cubic, 8 is 2 cubic, so 4 cubic, 64 cubic should be filled

How to do the problem of finding the law of numbers?
The third party of junior high school is preparing for the middle school entrance examination, because it is too lazy, so I didn't do much to find the law of numbers in the past, otherwise I still can't understand
For example, if you use n to express the law, you will feel dizzy at first sight, and you don't want to see the answer

1. Look at the relationship between numbers and natural sequence of numbers, such as: 1,4,9,16,... Compare 1,2,3,4,... Obviously a (n) = n ^ 2.2, the sum of the difference between numbers before and after comparison, such as: 1,1,2,3,5,8,... Obviously the sum of the first two equals the third, a (n) = a (n-2) + a (n-1), (n > = 3). (Fibonacci sequence) again, such as: 1,2,4,7,11,16

The law of numbers
one
2 3 4
5 6 7 8 9
10 11 12 13 14 15 16.
What is the sum of all the numbers in the first line to the tenth line?

There are 1 + 3 + 5 + +(2 × 10-1) = 81
Sum equals 1 + 2 + 3 + +81=（1+81）×81÷2=3321

In △ ABC, ∠ C = 80, AC = BC, M is a point in the triangle, and ∠ MBA = 30, ∠ mAb = 10?

Sweat.. dizzy proof.. ok.. if you can give more points.. thank you first.. OK ~ back to the subject ~ auxiliary line is very complex ~ please see~
Extend am to BC at point E, extend BM to AC at point F, make CD perpendicular to AB, cross BF at point G, cross AB at point D, connect AG

In the plane ABCD, e is the point on AB, f is the point on BC, and the angle EDF is equal to 45 ° to prove AE + FC = EF
By the way, it's a square. Sorry

Is there a lack of the condition that ABCD is a square? If it's a square, it's very simple. Extend BC to g to make CG = AE. I believe you can do the rest

1/1,2/1,2/1,3/1,2/2,1/3,4/1,3/2,2/3,1/4.
1 / 1 means 1 / 1
Number one: 17 / 30 is the number one in this series
2: What's number 50?

The results show that the order of numerator is 1,2,2,3,2,4,3,2,1; the order of denominator is 1,1,1,1,2,3,1,2,3,4; the rule is that the sum of numerator and denominator is 2, one 3, two 4, three 5, four, and the denominator gradually increases from 1 to 1, while the numerator gradually decreases. 1) 17 + 30 = 47, in the first + 2 + 3 +... + 46 + 30 = 4

10/(12)+20/(123)+30/(1234)+40/(12345)+...+90/(123456489*10)=?

Original formula + 10 / (1 * 2 * 3 * 4 * 5 * 6 * 4 * 8 * 9 * 10)
=10/(1*2)+…… +80/1*2*3*4*5*6*4*8*9)+90/(1*2*3*4*5*6*4*8*9*10)+10/(1*2*3*4 *5*6*4*8*9*10)
=10/(1*2)+…… +80/1*2*3*4*5*6*4*8*9)+ 100/(1*2*3*4*5*6*4*8*9*10)
=10/(1*2)+…… +80/1*2*3*4*5*6*4*8*9)+ 10/(1*2*3*4*5*6*4*8*9)
=…………
=10/(1*2)+10/(1*2)
=10
So the original formula = 10-10 / (1 * 2 * 3 * 4 * 5 * 6 * 4 * 8 * 9 * 10)
=How much do you count

1. There are 6 students in group A, with an average of 140 times per minute. If group B has an average of 160 times per minute, how many students are there in group B?
2. Fruit sugar is 12 yuan per kilogram, and milk sugar is 10 yuan per kilogram. How much yuan per kilogram of this kind of sugar should be sold when mixing 5 kg fruit sugar with 3 kg milk sugar?

1. There are 6 people in group A, 152-140 times less than the average
6 * 12 = 72 times less than 6 people
Group B: 160-152 times more than average
So group B needs 72 / 8 = 9 people
2. (12 * 5 + 10 * 3) / (5 + 3) = 11.25 yuan

Four players with the numbers of 101126173193 compete in table tennis. It is stipulated that the number of sets for each two players is the remainder of their number and divided by 3. Then the player with the most sets plays______ It's a dish

101+126=227，2+2+7=11，11÷3=3… 2；101+173=274，2+7+4=13，13÷3=4… 1；101+193=294，2+9+4=15，15÷3=5；126+173=299，2+9+9=20，20÷3=6… 2；126+193=319，3+1+9=13，13÷3=4… 1. 173 + 193 = 366, 3 + 6 + 6 = 15, 15 ／ 3 = 5; the number of plates of No. 101 player is 2 + 1 + 0 = 3 (plates), the number of plates of No. 126 good player is 2 + 2 + 1 = 5173 player is 1 + 2 + 0 = 3 (plates), the number of plates of No. 193 player is 0 + 1 + 0 = 1 (plates), a: the player with the most plates is No. 126, who has played 5 sets

The following is a regular array of triangles (1). If you look at the array carefully, what rules do you find? The first line: 1 the second line 1 the third line one 1 1 1 2 1 1 3 3 1 1 4 6 4 1 1 5 10 10 5 1