Part 4:
Teacher and Students Presenting
Alternative Solution Methods [Begin:
21:40]
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The teacher introduces
another method by saying, "Ive thought about
it too, so... what do you think about this way of
thinking." He then describes a method of subtracting
off the savings of a cheaper cake (30 yen) from the
amount needed to buy all delicious cakes (2300 yen). One
would need to subtract seven times to get below the 2100
yen, so one could buy only three delicious cakes. Not all
students understand his explanation so he asks another
student, whom he knows has used an algebraic inequality,
to explain. The student verbally describes the inequality
230x + 200(10-x) < 2100. After the students
presentation, the teacher challenges students to come up
with explanations that others can understand. |