Lets convert all units in to meters.
The length of rope she gave to her brother = 475.6 cm
1m = 100cm
475.6/100 = 4.756m
The length of rope she gave to her sister = 5230mm
1 m = 1000 mm
5230/1000 = 5.23 m
So the amount of rope she gave to her brother and sister in meter = 4.756 + 5.23
4.756
+5.230
_______
9.986
That is 9.986 m.
The amount of rope left with Hima = 15.98 - 9.986
15.980
- 09.986
_______
5.994
Hima has 5.994 m of rope left with her now.