What is the 489th digit in the number 123456789101112...?

Answer: (d) 9

The numbers 1 to 99 use 9 + 180 = 189 digits. The remaining 300 digits cover exactly 100 three-digit numbers, 100 to 199, so the 489th digit is the final 9 of 199.

1. Digits from 1–9: 9. Digits from 10–99: 90 × 2 = 180. Total so far: 189.
2. Digits still needed: 489 − 189 = 300, all from three-digit numbers.
3. 300 ÷ 3 = 100 exactly, so the 489th digit is the last digit of the 100th three-digit number.
4. The 100th three-digit number is 100 + 99 = 199; its last digit is 9.
5. Check: digits 487–489 are 1, 9, 9 (from 199), and digit 490 is the 2 of 200.

Remember · Count digit blocks: 9 one-digit, 180 two-digit, 2700 three-digit. An exact division means the digit is the last one of that number.

Question and answer: UPSC's official GS Paper II (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). · Report an error