If two or above digit of an integer are separated and put in order, it becomes
1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 0, 1, 1, 1, 2, 1, 3, 1, 4, ----.
What is the 250th number of this sequence of numbers?
What is the 250th number of this sequence of numbers?
Answer
Solution
Number of the numbers of one digit is 9.
Number of the numbers of two digits from 10 to 99 is 2 × 90 = 180.
9 + 180 = 189.
After 189 pieces is a number of three digits. 250 - 189 = 61.
Since three digits number consists of three numbers, you can calculate how many three digits numbers are comprised in 61 pieces.
61/3 = 20 remainder 1
This shows that 250th number is the first number of 21st three digits number.
21st three digits number is 120 and the first number of 120 is 1.
1
Number of the numbers of one digit is 9.
Number of the numbers of two digits from 10 to 99 is 2 × 90 = 180.
9 + 180 = 189.
After 189 pieces is a number of three digits. 250 - 189 = 61.
Since three digits number consists of three numbers, you can calculate how many three digits numbers are comprised in 61 pieces.
61/3 = 20 remainder 1
This shows that 250th number is the first number of 21st three digits number.
21st three digits number is 120 and the first number of 120 is 1.
