is this a writing technique

why does the writer use "one fifth" rather than percentage of 20% to go with the rest of the paragraph?  is it to trick the reader? http://www.economist.com/node/21526350 

cat sitting

IRENE

humans panic.  fear is such a strong driver.  thats why i bought gold and left it and left

pann

last last sunday.  i was going to meet mikey for dinner.  but he decided to be really late

word play. foreplay.

word play. fore play. australia.  u owe me. 6 dollars for a cab. i love the power move.  finger

probability

life's all about probability isn't it?  u just want to place yourself at the best place at the