Eight natural numbers, starting from the third number, each number is equal to the sum of the first two numbers. Given that the first number is 3 and the eighth number is 180, what is the second number?

Eight natural numbers, starting from the third number, each number is equal to the sum of the first two numbers. Given that the first number is 3 and the eighth number is 180, what is the second number?

Let the second number be a
Then the third number is a + 3
The fourth number is 2A + 3
The fifth number is 3A + 6
The sixth number is 5A + 9
The seventh number is 8A + 15
The eighth number is 13A + 24 = 180
The equation a = 12 is obtained

There are ten natural numbers. Starting from the third number, each number is equal to the sum of its first two numbers. What is the seventh number?
How urgent!

Let the first number be X,
The second number is y,
So the third number is x + y,
The fourth number is x + 2Y,
The fifth number is 2x + 3Y,
The sixth number is 3x + 5Y,
The seventh number is 5x + 8y,
The eighth number is 8x + 13y,
The ninth number is 13X + 21y,
The tenth number is 21x + 34y,
So the total is: 55x + 88Y = 2002 (1001 = 7 * 11 * 13)
That is, 5x + 8y = 182 is the seventh number

Eight natural numbers are arranged in a row. Starting from the third number, each number is the sum of the two numbers in front of it. Given that the fifth number is 7, then the eighth number is 7______ ．

Suppose the first number is x, the second number is y, then the third number is x + y, the fourth number is x + 2Y, and the fifth number is 2x + 3Y, that is, 2x + 3Y = 7; because X and y are natural numbers, so x = 2, y = 1; the eighth number is 8x + 13y = 8 × 2 + 13 = 29, so the answer is 29