Digit 3 in thousands place no increase because number after its 178 is smaller than 500. Digit 4 in thousands place increase by 1 because number after its 720 is greater than 500. Digit 5 in thousands place increase by 1 because number after its 510.4 is greater than 500. Digit 9 in thousands place increase by 1 because number after it is equal than 500.