use the digits 1-7 to create a seven digit number that can only be rounded to 6,300,000

Question

solve with a four step plan

Answer 1

Assume rounding to the nearest hundred thousand.

Second digit must be 2 and the third digit must be 5 or more. We could use the largest digit available which is 7, so we have 627 as the first 3 digits. There are 4 digits left, so we could order them in descending order: 6275431.

That is: 6,275,431.