Determine the number that results in 750 when approximated to the nearest ten, given that
the sum of its digits is 20.
Since the unknown number results in 750 when approximated to the nearest ten, we know that the number must be greater than or equal to 745 and less than or equal to 754.
Check the sum of the digits of each number in this range.
The only 3 digits with a sum of 20 is , so the unknown number is 749.