2. The solution is similar. The number of wheat in the nth grid is twice that in the nth grid, so the second grid is the second power of 1, the third grid is the second power of 2, and the fourth grid is the third power of 2 ... The nth grid is the second power of (N- 1). So the last grid number is 2 to the 63 rd power. I don't know if you have studied geometric series, but it is easy to find that the total number is 2 64- 1(2- 1 to the 64th power).