How many different positive integers exist between 106 and 107, the sum of whose digits is equal to 2?

• first of all ,it is 10^6 and 10^7
  So, the numbers should be from 1,000,000 to 10,000,000
  
  The following two cases are possible for the sum of the digits to be 2:
  1. Two 1's and the rest are 0's:
  1,000,001
  1,000,010
  1,000,100
  1,001,000
  1,010,000
  1,100,000
  
  6 numbers.
  
  2. One 2 and the rest are 0's:
  2,000,000
  
  1 number.
  
  Total = 7 numbers.
• 8 years agoHelpfull: Yes(0) No(0)