In the first part, the teachers dictate the exercises (meaning verbally without symbolic form) for learners to write on their notebook under the title "mental maths"
There are 12 items and each item is about multiplying, adding, subtracting and dividing positive integers. Finding a square, a square root, a cube, a cube root of a number, adding and subtracting and multiplying decimal, adding, subtracting and multiplying fractions. Learners are asked to work on these for about 10 minutes.
The pattern of activity and interaction in this activity can be described below.
After learners wrote the items in their notebook and having chance to , the teacher asks all learners to answer number one and write it down on learner's white board (its size is about ...). Once the learner finish, he or she holds up the board to show the answer to the teacher. The teacher responded by saying "Yes", "good", "nice", "correct" or "beautiful" for the acceptable answer or saying "No" for unacceptable answer.
The difficulties faced by some learners are to write the items in symbolic form such as the square, the cube, the square root and the cube root. When learners are asked to write the square root of 9, a learner write 81=9. See p.6.
They also find it difficult to differentiate among them. For example, when learners are asked to write the cube root of 27, a learner write v27. In this phase, there is none explanation about the differences and the relationship between square and square root, also between cube and cube root. The only short explanation in relation to this is in the beginning of Part 2, by saying "square, having an exponent two" and "cube, having an exponent 3. See page 3.
Another clear issue for learner is to find 67 subtract 94. This is indicated by various answer offered by different learners such as 3, -33, 74, -30, -27, 73, (see page 4).
The teacher several times invite learners to show their answer in front of the class, but no students take this offer. Until a learner offer a correct answer, negative 27, and the teacher confirms, saying "that's the correct answer". In this event, the teacher doesn't explore learner's reasons of the correct and incorrect answer.
Despite many problems faced by learners, the teacher announces a new topic to be learned "Multiplying ....."
In this part, the teacher presents four examples and these require a fluency of dealing the items presented in Part 1.
The First example is multiplying fractions with all numerators and de numerators are exponent with the same bases.
The teacher instruct learners to expand all the exponents and telling about what to do. Quote "see p.11"
After that she invites learners to take turn to cancel one pair, until no more pair to cancel, and finally asking question:
"Are we left with any 2 on top? It means what do we have? Learners offer different answer: 4, 1, 1 over 4, which is the correct answer. Teacher that confirm the correct one.
The second example is similar with the first but the basis of the exponent are not the same. As a result, when it is expanded, no pairs to be cancelled. The teacher says, "We don't have pairs we can divide, so what do we do then?"... After expanding "you must multiply all of them"
Both examples are presenting "localized nature of the rule".
The rule of canceling cannot be applied in the second example. The rule of multiplying all the numbers in the numerators/denominator might be ineffective in another case. The teacher present her choices on procedure, without offering chance to get learners strategies or without reflecting on why is the certain ways works or doesn't works. Presenting particularly without acknowledging the generality or the principled ideas.
In the third examples, it contains square ..... In the numerator or denominator.
The teacher led learners to work on each.
See how learners responded.
The in fluency in the first part of the lesson seemed impact on the difficulties in working on this exercise.
Catatan:
Dari tulisan ini, saya telah menunjukkan localised. Bagaimana dengan explanation.
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