if m is the sum of all 3 digit no which is formed using 2,3,4,5,6 with no repeated digit,find range of m?

Answer 1

I understand this to mean the sum of the 60 numbers 234, 235, ..., 654 (three digit numbers), but then m has one value, not a range.

By the way, there are 60 of these numbers since, as you construct one of the numbers, there 5 choices for the first digit, 4 for the second, 3 for the third, giving 5*4*3 = 60 possibilities.

And here's m. Think about the units digits in the sum. Each digit 2, ..., 6 appears 12 times in the last digit, and that sum is 12*(2+3+4+5+6) = 240, so m ends in 0 and has a "carry" of 24 to the tens digit. So that column sum is 264, write the 4, carry 26 (starting to sound like a Tom Lehrer song). Sum of the first digits with the carry is 266, giving m = 26640.

Answer 2

The sum of all 3 digit numbers made up of 2, 3, 4, 5, 6 with no repetitions is constant.

Therefore the range is 0.