arithmetic

I continued to do arithmetic with my father, passing proudly through fractions to decimals. I eventually arrived at the point where so many cows ate so much grass, and tanks filled with water in so many hours I found it quite enthralling.

--Agatha Christie (1890 - 1976)


Arithmetic for Parents by Ron Aharoni
What I Learned in Elementary School by Ron Aharoni (in American Educator)

from ktm-1 (you may have to hit refresh a number of times):
Aharoni article, part 1
Aharoni article, part 2: America's 'new math' goes to Israel
Aharoni on the fifth operation of arithmetic
Ron Aharoni on teaching fractions & forming units