what fraction of the numbers from 1 to 1000 have the digit 7 as the least one of the digits

Answer 1

Of one-digit numbers (1 to 9): 1
Of two-digit numbers (10 to 99): 10 + 8 = 18
Of three-digit numbers: (100 to 999): 100 + 80 + 9x8 = 252
Of 4-digit numbers (1000 only): 0
Total: 271

Answer 2

nuber less than 32 am a multiple of 3 the digits of my number add up to 6

Answer 3

How can you make the sum of 12 by using only 3 digit odd numbers and are not used twice?