Slide Rule Bracelet

These bracelets are the C and D lines of a slide rule, and can be used to multiply and divide numbers. The full line represents the 'one' index and the integers 2 through 9 are indicated with long ticks and raised dots. The shorter ticks mark every tenth of an integer (2.1, 2.2, etc.).

To multiply numbers, align the index on the bottom bracelet with the first number to multiply on the top bracelet. Then find the second number to multiply on the bottom bracelet without rotating the bracelets relative to each other. The adjacent number on the top bracelet will be the product of the two numbers. To divide, do this process in reverse: Align the dividend on the top bracelet with the divisor on the bottom bracelet, and the bottom bracelet's index will be aligned with the quotient on the top bracelet.

The multiplication lines on slide rules use a logarithmic scale to convert multiplication into addition: (log10 3) + (log10 2) = (log10 6). The base 10 logarithm makes the numbers 'wrap,'