A slide rule. Used for making mathematical calculations before electronic calculators.

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Size: 5472px × 3648px
Location: UK
Photo credit: © Ian Gibson / Alamy / Afripics
License: Royalty Free
Model Released: No

Keywords: aid, analyse, analysis, analytical, analyze, arithmetic, arithmetical, brainy, calculating, calculation, clever, computation, computational, engineering, geeky, math, mathematics, maths, obsolescence, obsolete, rule, science, scientific, slide, sum, tool