4 3/104310 can be written as an improper fraction
color(white)("XXX")(4xx10+3)/10=43/10XXX4×10+310=4310
3 3/5335 can be written as an improper fraction
color(white)("XXX")(3xx5+3)/5=(18/5)XXX3×5+35=(185)
18/5185 can be written with a denominator of 1010 to match the 4 3/10=43/104310=4310 term
color(white)("XXX")(18xx2)/(5xx2)=36/10XXX18×25×2=3610
Therefore
color(white)("XXX")4 3/10 - 3 3/5XXX4310−335
is equivalent to
color(white)("XXX")43/10 - 36/10XXX4310−3610
color(white)("XXX")=7/10XXX=710