Answer
$\overline{V}DCCCXLVII$
Work Step by Step
RECALL:
$M=1000
\\D=500
\\C=100
\\L=50
\\X=10
\\V=5
\\I=1$
(1) When a smaller numeral is written before a bigger numeral, the smaller numeral is subtracted to the bigger numeral.
(2) When a bar is written on top, the value is multiplied by 1000.
Note that:
$5847 = 5000+800+40+7
\\5847=5000+500+100+100+100+(50-10) + 5 + 1 + 1
\\5847= \overline{V}DCCCXLVII$
