ENG display mode on HP-15C

[Pekis]

The significant digits are already present in the calculated number (178 in my example).

I see the ENG display as a special "Unit" display (E-3 in my example are mm); After the unit digits come the decimals but the unit digits must first be displayed without rounding if possible !

So we have 178 mm, and that number can be displayed ... who would want to see 200 ?