Answer:
700,000
Step-by-step explanation:
Round off all the numbers after the first number
If rounded off and the number closest to the first no is 5 and above, it automatically approximates the next number to its left.
Example: 681,858
The last no is 8, it therfeore approximates 5, thereby changing it to a 6
After being changed to a 6, it approximates the next no to its left, 8, turning it into a 9, nine approximates 1, turns it to a 2, two can't approximate, it's below 5, move on to 8, eight approximates 6 turning it to a 7, that's how I got my 700,000.