if function 3 variables

hi can anyone help with this , or let me know if this is even possible.

Thanks

Format a cell with 3 different rules

If a1=1 , the add b1+c1+d1 in cell e1
If a1=2, then add c1+d1 in cell e1
If a1 =3, then copy d1 to e1

Try this formula in E1... nested IF statements...

=IF(A1=1,B1+C1+D1,IF(A1=2,C1+D1,IF(A1=3,D1)))

Thanks djapigo, you're a lifesaver !!