The sum of all the numbers in the sequence 1,2,3,... 10000? The answer is 180001
All the numbers are represented by five digits. Adding 0 and 0 before less than five digits will not affect the sum of the numbers. 1 means that the numbers on 00001 digits are 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 A group of 10 cycles, 1000 groups, sum of numbers = 45 × 1000 = 45000, the numbers on the ten digits are 0, 0 (9), 1,1 (10), 2, 2 ...