#### HamsterJam

##### Established Member

I thought the Sinclair had 5 digit mantissa (unit plus 4 decimal places). Will have to dig mine out and check. - Edit: just realised mantissa is the part after the decimal point. So agreed, unit plus 4-digit mantissa.That is asking for 6 significant figures - so you are/were not comparing like-for-like.

The Sinclair had only a 4 figure mantissa so the best you would ever get would be 5 figures (It did hold another digit in memory so the last one displayed would be accurate). The HP-35 had 10 significant figures but of course cost nearly 3½ times as much.

My needs at that time were household & model-making so seldom greater than 2m.

It's interesting to realize today's cost equivalents --- Sinclair £566 - HP-35 £1905

I also have a Casio fx81 someone referred to. My parents bought it for me when I did maths A-level (which dates me). I never switched it off as it powers down after a few minutes of inactivity and the 2xAA batteries last years. (Unlike the Sinclair which could eat a set of AAAs in a single maths lesson).

I used it extensively for 15-20 years of my engineering career when Excel took over. A mate had the same calculator and soldered his power switch permanently on when it failed.

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