Interpreting Standards as
Sense-Making Opportunities
Sue Pawula
Summary
Algorithms
created by students can be one tool to use when teaching them to make sense of
math. In this article, this approach is initiated through in lessons targeted
at teaching students:
“Understand
subtraction of rational numbers as adding the additive inverse, p-q=p+(-q).
Show the distance between two rational numbers on the number line is the
absolute value of their difference, and apply this principle in real-world
contexts. (7.NS.c)
Instead
of teaching students the “keep-change-change” method, it is suggested that
teachers should model the procedure and then ask students to work
independently. The old method
could hinder student sense-making of subtraction with rational numbers or
connections to related subtraction ideas.
When students can think about subtraction in terms of distance or vector
length they are provided with chances to connect their actions in a visual space
to operations on numbers. This
also should allow the teacher to elicit student reasoning that will indicate
their connections and meaning that they assign to mathematical procedures. In this instance it allows students to
develop their own algorithms for rational number addition and subtraction. This
takes more time and requires teacher commitment to content coverage in order to
arrive at the student goal.
However, it requires students to have conversations about the patterns
they see related to adding and subtracting rational numbers in a variety of
different problem contexts. The
teacher will observe that this activates students to form conjectures about the
patterns they have noticed and discussions will allow students to express these
conjectures to their peers. During
the discussions, students will need to use precise mathematical language,
establish standards of evidence, and focus on patterns that will be useful when
they later develop algorithms. The
teacher will also notice that some of their conjectures are ambiguous or
incorrect because some students are unable to distinguish between relative and
absolute values of the numbers.
Teachers can use this opportunity to formally define absolute value. Students can acquire deeper
understanding of operations on rational numbers, by proceeding through these
steps and working as a group to generate a collective algorithm, which they
decide, is accurate, sensible or efficient. Following this student should justify the accuracy of the
algorithms in different ways such as number lines, chipboard models, or a few
examples that the algorithm works. The student understanding developed in this
manner is important since it allows students to flexibly experiment and use
rough-draft mathematical language to convey their final outcome.
Reflection
Although this was a time consuming
activity, the outcome allowed the students to build flexibility in
thinking. It gives them control of
the learning process and allowes the teacher to facilitate while allowing the
students to experiment and reflect, discuss, and discover different ways to
reach the goal. This kind of
learning is very important to expansion of individual cognitive
development. It also encourages
students to work in teams and share information, rationalize, and debate the
different ideas, and come to provable conclusions. Teachers need to plan how they would implement this type of
student learning, being mindful of the time constraints. Even so, this is an excellent way to
move student thinking onward and upward and let them work on projects, individually
or in teams, the same as they would have to in the real world
Choppin, J. M., Callard, C. H.,
& Kruger, J. S. (2014). Interpreting standards as sense-making
opportunities. Mathematics Teaching in
the Middle School, 20(1), 24-29.