Mathematics
Answer
For the greatest 6-digit number using exactly three different digits, the digits at the higher places should be as large as possible.
Use the digit 9 as many times as possible (without exceeding three different digits in total).
Using 9 four times makes only 3 different digits (9, 8, 7) when combined with 8 and 7. Let us check: in the number 9,99,987, the digits are 9, 9, 9, 9, 8, 7. The different digits are 9, 8 and 7, which gives exactly 3 different digits.
Arranging in descending order: 9, 9, 9, 9, 8, 7.
The greatest 6-digit number = 9,99,987.
Hence, the greatest 6-digit number using three different digits is 9,99,987.
Related Questions
Write the greatest 4-digit number having distinct digits.
Write the smallest 4-digit number having distinct digits.
Write the smallest 7-digit number using four different digits.
Write the greatest and the smallest 4-digit numbers using four different digits with the conditions as given:
(i) Digit 7 is always at units place.
(ii) Digit 4 is always at tens place.
(iii) Digit 9 is always at hundreds place.
(iv) Digit 2 is always at thousands place.