The first triangle is filled with 0 and the second triangle is filled with 1 The rule is to subtract the two numbers above, and then subtract the difference from the number below. Then fill in the number in the middle of the third triangle as 2,25-17 = 8, and the following number is 10, so the following rule is obtained, which is 65438+. 15, so the fourth lowest number is 15, the middle number is 3, and the upper left number is 29. The final answer is 0, 1, 2, 10, 29,3, 15.