TERC Hands-On Math: A Snapshot
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For A Review of the Second Edition of TERC math, click on:
2008 TERC Math
vs. 2008 National Math Panel Recommendations
Developed by TERC,
with funding from the National Science Foundation (NSF), Investigations
in Number, Data, and Space purports to be "a
complete K-5 mathematics curriculum that supports all students as they
learn to think mathematically."
The
NSF is now spending millions to promote implementation of the TERC
program.
School Boards find it difficult to say no. They rationalize: "it's just
a different way to teach elementary math, and the NSF backs it, so how
bad can it be?"
This program is very
bad
because it omits standard computational methods, standard formulas, and
standard terminology. TERC says this is now obsolete, due to the
power of $5 calculators. They claim their program moves “beyond
arithmetic” to offer "significant
math," including important ideas
from
probability, statistics, 3-D geometry, and number theory.
But math is a
vertically-structured
knowledge domain. Learning more advanced math isn't possible
without
first mastering traditional pencil-and-paper arithmetic. This truth is
clearly demonstrated by the shallow details of the TERC fifth grade
program.
Their most advanced "Investigations" offer probability without
multiplying
fractions, statistics without the arithmetic mean, 3-D geometry without
formulas for volume, and number theory without prime numbers.
TERC Omits All
Standard Computational
Methods
Consider the "Sample of
Ads
Investigation," at the end of the TERC fifth grade. Students are
given a 48-page newspaper and a supply of "Recording
Strips" that are premarked with "familiar
fractions," such as 1/4 and
2/3.
They begin by deciding to sample one-third of the 48 pages. After
using a calculator to divide 48 by 3, they select 16 sample pages and
use
eyeball estimation to guess the fraction of ads found on each sample
page.
Then, using one 3-inch “Recording Strip”
for each sample page, students color the fraction of ads, cut out the
colored
portions, and tape them onto a 48-inch length of adding machine tape, “starting
from one end of the tape and putting the pieces right next to each
other.”
Students then estimate the fraction of ads for the full 16-page sample
by folding the 48-inch strip to estimate the fraction corresponding to
the 16 colored-in pieces.
Why not add the 16
fractions
and then divide the sum by 16? TERC students never learn about
dividing
fractions, and they never learn general methods for adding
fractions.
They do learn a hands-on method for adding two proper fractions with
denominators
less than 7, but this paper-folding method doesn't work if the
denominator
of the sum fraction isn't also less than 7.
TERC Omits Standard
Formulas
For the final fifth grade
Investigation
in 3-D geometry, TERC students use patterns, scissors, and tape to
build
prisms, pyramids, cylinders, and cones. They then attempt to “discover”
3 to 1 volume relationships by pouring rice from one bulging container
into another. Later they find the volume of each paper container
by pouring rice from the container into a plastic measuring tool.
Why not formulas for
volume?
TERC says students usually don't understand formulas and frequently
apply
them blindly and incorrectly. So general methods involving
standard
formulas are not found in TERC math.
TERC Omits Standard
Terminology
TERC recommends natural
language,
not standard terminology. For statistics they say "we
have found useful such words as clumps, clusters, bumps, gaps, holes,
spread
out, and bunched together."
For "the mathematics of change" they
recommend "grow, shrink, faster, slower,
steep,
flat, slow, steady, speed up, slow down, grows steadily, grows faster
and
faster, grows slower and slower, shrinks steadily, shrinks slower and
slower,
shrinks faster and faster, grows and then shrinks, oscillates between
growing
and shrinking." TERC appears
to believe that these subjective terms are related to calculus.
TERC has redefined the
meaning
of "think mathematically"
and painted a false picture of elementary mathematics. It’s all
very
hard to believe, but it's sadly true.
For a detailed
analysis of TERC math, click on TERC
Hands-On Math: The Truth is in the Details.
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Copyright
2002-2011 William G. Quirk, Ph.D.