# Multiplication Two digit numbers and one digit number

Classroom Observation in SD Muhammadiyah 1 (Fifth Report)

INTODUCTION

Multiplication is one of the subjects in mathematics that consist of some materials. Because the time was not enough to teach it in one meeting, in SD Muhammdiyah 1, that subject was taught in some meetings for third grade students. Classroom observation in SD Muhammadiyah 1 that was performed on October 7, 2010 was the series of previous observations that had been done on September 30, 2010. In the previous observation, students were taught about multiplication between one number and one number, such us 7 x 9, etc. The result of observation in the last observation was most of students have understood multiplication of one number and one number. At this time, this observation was hoped could help them to understand too multiplication of two numbers and one number, such us 46 x 5, and multiplication of two numbers and two numbers or other complex multiplications.

GOAL

The goal of this observation was to observe how students can construct their understanding about multiplication of two numbers and one number and how they can solve all the questions that had been given by the teacher.

OBSERVATION QUESTION

Did the students can understand concept of multiplication of two numbers and one number?

DATA DESCRIPTION AND ANALYSIS

In the beginning of teaching and learning process about multiplication of two numbers and one numbers, the teacher reviewed material about multiplication of one numbers and one numbers. As it had been learnt in the previous meeting, most students could answer the given questions correctly and they also could determine variety of multiplications to get the certain number.

This result showed that actually the students had known about multiplication of two numbers and one numbers. This was good improvement of the students’ understanding about multiplication because in the previous meeting, students just could make variation of multiplication like below:

18 could be resulted from multiplications:

6 x 3

3 x 6

1 x 18

18 x 1

21 could be resulted from multiplications:

1 x 21

21 x 1

7 x 3

3 x 7

In the previous meeting, they had also known multiplication of two numbers and one numbers, but it was just the multiplication of the number itself and one. Then, in this meeting students could determine that 36 could be resulted from 18 x 2, and 72 also could be resulted from 2 x 36, etc.

After the teacher reviewed the material in previous meeting, she gave some questions about multiplications of two numbers that give result more than two numbers (for multiplication that give result two numbers had been taught in second grade).

These were the questions and the students’ answers:

Students who tried to answer the questions in front of the class could give the right answers although some of them did it in long time. When there was a student that couldn’t answer the question rightly other students raised their hands because they wanted to answer it.

There were some ways that students used to solve the questions and they also did them by their own way.

From the picture above, on the whiteboard was it student’s answer. He solved the questions using his knowledge about position value in numbers, so he could get the answer. Even though it spent more time for him to solve it, he did it in the right way. He wrote the multiplication first, such us he wrote 6 x 3 = 18 and 50 x 3 = 150, than he moved into the question and got the answer. Once again, we can see that the student has already mastered position value material and could connect his new knowledge with the previous one.

Besides using, we can say “the long way”, there were some students that directly solved the problem by another way, here we can say “the short way”. The picture above showed one of the students who did it by the short way. When observers asked how he can use that way and how he can get the answer, he said that he has already known about multiplication from second grade of elementary school. It means that he has learnt it when he was in the previous class. The teacher also said that the material about multiplication has been learnt before. Students also still used their fingers to count some numbers. If it was hard for them to solve the questions, they stopped for a while then be silent looked so serious. When it was asked, they said that they counted in their mind, sometimes they used their finger to make it became real.

The other way that students used to solve the questions was addition. At the beginning, to solve the questions a few students added the same number as they learnt about basic multiplication. For example 56 x 3 = 56 + 56 + 56, here they could get the answer. In the presentation section beginning, some students went to the front, wrote their work and tried to explain their way how to get such a result.

At that section, the other students paid attention to their friend explanation and when there was a mistake that was made, they shouted that was false and made it into the correct one. They were enthusiast to follow teaching and learning process. Sometimes, when their friend stacked in answering, they immediately raised their hands and went to the front to finish it. When we observed students who still used addition in solving the questions, after listening their friend explanations and answers, they made those ways in their book that were same with their friend works which were the long way and the short way. They tried to make it by themselves.

Finally all questions could be answered by the students. The teacher showed the answers then all of the students in the class were asked to looked at the board and analyzed whether the students’ answer were right or need to be corrected.

CONCLUSION

To teach multiplication of two numbers and one number, the teacher reviewed previous materials and gave chances for students to find the right answers by their own understanding that they had known. In this class the teacher also gave chances for the students to analyze other students’ answer, so they could examine the answers of each other so that finally it led them to know the right answers.