don steward
mathematics teaching 10 ~ 16

Tuesday, 25 March 2014

percent 'of'

it's probably time to dispense with percentages as 1 is just as convenient a common measure as 100...

it's a historical quirk that we have percentages - they have been around for a while

Wikipedia claims that they were evident in Ancient Rome,
emperor Augustus levied a tax of 1/100 on goods sold at auction

as denominations of money grew in the Middle Ages, computations with a denominator of 100 became more standard and from the late 15th century it became common for arithmetic texts to include such computations
many of these texts applied these methods to profit and loss and by the 17th century it was standard to quote interest rates in hundredths

as '% of' operators, my view is that percentages should be turned into decimals from the outset, and ongoingly...

including an exploration of the relatively unused percentage key on a calculator

this task can become fiercely competitive!
note: there is no number 9 involved and no repeated digits are allowed

this is intended to be done mainly mentally
many fairly dull questions that, with 'minds-on' calculations, might prompt some consideration about connections

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