Uploaded February 2025 | Updated September 2026, 2 hours ago

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Despite being made from cardboard, this was a pretty powerful tool back in it's day. In this video we check out a cardboard slide rule that I found inside an old book a while back. We'll go over it's features, and do a few simple calculations on it.

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00:00 Overview
00:42 How it Work
01:52 Multiplying 2 times 4
02:23 Trailing Zeros and Decimals
03:35 Converting Inches to Metric
04:27 The Backside
05:24 Outro