HP 55 Hewlet-Packard Scientific Calculator |
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| "Introduced on January 1 1975, this was the sixth handheld electronic calculator sold by HP, and the fourth scientific model. Its code name was "Merlin" - something to do with wizardry, no doubt." Wlodek Mier-Jedrzejowicz. | |
| Source: MoHPC - The Museum of HP Calculators | |