|Long car trips have me staring at the horizon, mentally tracing and altering patterns and planning adjustments. Since I've become increasingly intrigued with European patterns, I often find myself trying to convert cms to inches in my head. I don't speak Metric system, much less *think* in metric. All I know is the rough translation: 2.5 cm is approximately 1 inch. Because dividing the number of cm by 2.5 is more than I can do while attempting to stay in my traffic lane, I switched to a simpler method: double the number of centimeters and divide by 5. (You remember in Algebra I, when they told you that you could multiply both sides of an equation by a common number? Well, finally here's a practical application for that nonsense....). Example, my new Onion pattern size chart says the back length is 41cm. Double the 41 to 82. Divide by 5. (Mentally - no cheating with paper and pencil.) Answer: 16 and 2/5...so it's a little less than 16-1/2". Checking my answer on a "bilingual" tape measure: 41 cm is about 16-1/4". Not perfect, but good enough for those times when I am being held captive without a calculator and a tape measure.
Yes, I know...it's basic math, and since my name is not Pythagoras, it's definitely a "recycled" idea. Anyone who laughs gets to balance my checkbook.