The rule of double false position is an arithmetical procedure for evaluating linearly-related quantities. The method does not rely on variables or equations, but is based instead on interpolating between, or extrapolating from, two guesses, or suppositions. Although the technique is seldom mentioned today in North American curricula, it was routinely used in much of Europe, Asia, and North Africa from medieval times to the 19th Century, and is still taught in many classrooms there today. Historically, the approach was especially convenient for practical tradesmen whose knowledge did not normally extend to a mastery of algebra; they could pull the

EP - 38 ET - 1 PB - Mathematical Association of America PY - 2010 SN - 9780883851876 SP - 29 T2 - Mathematical Time Capsules T3 - Historical Modules for the Mathematics Classroom UR - http://www.jstor.org/stable/10.4169/j.ctt5hh8hc.8 VL - 77 Y2 - 2020/09/28/ ER -