(2×100)+(9×10)+(6×1)+(3×1/10)+(8×1/ 100)=
in standard form

We know that standard form = the number that is not expanded.
This equation is expanded so standard form =

2*100=200
9*10=90
6*1=6
3*1/10= 0.3
8*1/100=0.08

200+90=290
290+6=296
296+0.3=296.3
296.3+0.08=296.38

Your answer is 296.38
Hope this helped!