4th grade
posted by Elizabeht .
it is between 1 and 2 maillion. The first three digits are the same. The least possible digit is in the thousands place. The greatest possible digit is in the ones place. the hundreds digits is 1 more than the tens digit. The sum of the digits is 21.

The number must be 1,110,xy9.
I hope you see why. The first number must be 1 if the whole number is between 1 and 2 million. They then tell you what the second, third and lst digits are.
We just need to find digits x and y
x + y = 2112 = 9
The hundreds digit is 5 and the tens digit is 4.
The number is 1,110,549 
I think the number is 1,110,549
Hope I helped . 
use the digits 2,5 and 9 to make as many 3 digit numbers as you can put the numbers in order from least to greatest.