Terminated: unknown
The slider on the left enables constant calculations, where repeatedly pressing the += or −= key repeats the last multiplication or division. Repeatedly pressing the −= key changes the sign with each operation.
Very similar in design to the MBO micro ALGEBRA EC-8413
The battery compartment is made in such a way that it can be removed after sliding a lever. After changing the batteries, click it back into place.
This is one of the early additions to my museum. It was bought in the seventies by my father Henk Mulder for the bargain price of $150. It’s a beauty, with a fluorescent tube for every digit and the LED indicators. It is also one of my earliest scans, scanned on 1999-02-24. The perspective is all wrong and I might re-scan it one day.
Old though it may be, this calculator has been used extensively. You can even see that on the picture of the calculator, there is quite a bit of wear near the on/off switch! I must confess that when practising for prescool I quite often reached for this machine...
It’s really amazing when you realise that the HP 65 was introduced in the same year as this model (but, admittedly at a higher price).