The grade level for which the lesson is designed
This lesson is designed for teaching fifth grade learners on how to deal with mathematic questions that involve the rounding off of numbers to the nearest tenth. This is useful for them because, in their future, they will be dealing with numbers which will require the use of skills of rounding off. Therefore, they should be well equipped on dealing with rounding off of mixed decimals.
The prerequisite concepts and skills students have learned prior to this lesson
There are a few prerequisite concepts and skill that the fifth graders are expected to have learnt in their earlier stages of schooling before this particular lesson. According to Mounts (2011), the first concept they have to possess is the general ability to round off numbers. This means that they have to know the number 5 is the focal point of rounding off. A figure that is lower than 5 is reduced or lowered, while a figure that is greater than 5 is increased upwards. Secondly, the students should have the skills of rounding off whole numbers. This skills if learnt, prior to this class, will help them in dealing with the activities of rounding off decimal numbers. Thirdly, the fifth graders should be able to count from 1-100 in order to know the place values of numbers. Before beginning this class, I also expect that the students should have prior knowledge on the basic additional and subtraction of numbers. This is very useful in the rounding off of mixed decimal numbers.
Concepts and skills that will be presented in this lesson
The first concept that I will present in this lesson is that of place values. They will have to learn how to identify particular place value of a number in order for them to learn how effectively to round off numbers with decimal. Secondly, I will present to the students the skills of identifying numbers that are tenths and hundredths on the right side of the decimal point. They should be able to mark numbers which are tenths and round them off accordingly. The ability to identify and mark the number which is tenth in a given question will help the fifth graders to pay attention to that particular number. In this way, they will be able to know which number in particular needs to be rounded off.
How to teach rounding with decimals to the nearest tenth and the activities and tasks to be used
I will begin my lesson by teaching the fifth graders on how to identify numbers in the tenth and those in hundredths of place value. This is because they will be dealing with these numbers throughout their calculations. They will be taught on how to identify specific place values and mark the accordingly.
One of the tasks that I will use in this teaching process is the use of a number line. Here I will instruct students to draw a straight line on their books. A number line is normally calibrated from 1-9 in cases of whole numbers, however, since our lesson will be focusing on decimal numbers, and particularly to the nearest of tenths, our number line should be marked from 1.1-9.9. Here, 5 will be the focal point to their basis of rounding off. The number line will help in guiding them on the rule of five whereby a number that is less than 5 will be rounded down, hence no effect on the number in the tenths place value, while that more than 5 will be rounded off hence changing the number in the tenths place value.
After they have learnt this, I will give them activities with mixed decimal numbers whereby they will have to practice what they have learnt. It will include the use of numbers like 4.6u, 9.53, 7.26, 1.28, 3.33, and 5.47. The student will have to position these numbers on the number line and round them off accordingly.
In addition to the use of a number line, I will ask the students to come with twenty coins each, for practical use. I will also come with a projector to display the events so that the students have a visual perspective of what they are learning. I will give them practical tests after which I will move around the class and give assistance to those who encounter problems. All these are aimed at enhancing their understanding of this topic.
Three specific examples
In order to test their understanding of the topic, I will give them a test comprised of mixed decimals. The first test will be three decimal places, for example, 4.756. It will test whether they are able to identify 7 or 5 as the tenth number. Some students will get confused and will give their answer as 4.76, instead of 4.8 which is the correct answer. Secondly, I will repeat a given number in the end, for example, 8.66. The repetition of 6 may confuse some of them who will give their answer as 8.6 instead of 8.7 which is the correct answer. Thirdly, I will give them a number like 32.85. Here some of them will write 33 instead of 32.9 which is the correct answer. I will, therefore, go back and clarify these issues.
The Common conceptual and procedural errors
According to McDoniel (2009) one of the most common conceptual/procedural errors by students is that sometimes they do not round off the expected figure; instead they end up writing the tenth placed value number that has been put in the question. The second conceptual/procedural error committed by students is that they round off the whole numbers, forgetting that they should round off the decimal segment on the question.
References
McDoniel, M. (2009). How to teach rounding with mixed decimals to the nearest tenth.
Retrieved 11 June 2014. From, http://voices.yahoo.com/how-teach-rounding-mixed-decimals-nearest-2417344.html?cat=4
Mount, P. (2011). Fifth Graders Rounding Decimals: Is it Necessary to Learn to Round
Decimals? Retrieved 11 June 2014. From, http://voices.yahoo.com/fifth-graders-rounding-decimals-10569205.html
