What’s a slide rule and how are they so useful?
In: 11
Let’s say you want to multiply 43 x 89, but you don’t have a pen and paper, and you don’t have a calculator. Are there any mathematical tricks we might be able to use as shortcuts?
One is using properties of exponents and logarithms. 10^x * 10^y = 10^(x+y), no matter what x and y are. 43 is 10^1.663, and 89 = 10^1.949, so 43 x 89 = 10^(1.663 + 1.949).
A slide rule is a set of wooden or plastic rulers with logarithm tables visually printed on them. You would slide one piece representing the 89 to line it up to where another piece says 43, so that their lengths are back to back. Then you’re able to see what number is at the tip, and it is their product.
It looks super complicated at first, but ultimately it lets you multiply or divide any two numbers just by lining up special sticks and not needing to actually do calculations.
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