"JoeU2004" wrote...
....
Instead, try the following (rounding the 5th significant digit):

=--(LEFT(TEXT(B1,"+0.000E+0;-0.000E+0"),6) &
* * * MID(TEXT(B1,"+0.000E+0;-0.000E+0"),7,5))

Why not the far simpler

=--TEXT(B1,".0000E+000")

? Or

=ROUND(B1,INT(4-LOG10(ABS(B1))))

Or the following (truncating after the 4th significant digit):

=--(LEFT(TEXT(B1,"+0.0000E+0;-0.0000E+0"),6) &
* * * MID(TEXT(B1,"+0.0000E+0;-0.0000E+0"),8,5))

=TRUNC(B1,INT(4-LOG10(ABS(B1))))