The key here is the enthalpy of fusion for ice, which is given to you as
#DeltaH_"fus" = color(blue)("333.55 J") color(white)(.)"g"^(-1)#
For a given substance, the enthalpy of fusion tells you the amount of heat needed in order to convert
In your case, you know that in order to turn
This means that your sample will require
#1.8 color(red)(cancel(color(black)("g"))) * color(blue)("333.55 J")/(1color(red)(cancel(color(black)("g")))) = color(darkgreen)(ul(color(black)(6.0 * 10^2color(white)(.)"J")))#
The answer is rounded to two sig figs, the number of sig figs you have for the mass of the sample.