Decimal Place Value
The target of teaching on how to round to the nearest tenths would be the student on the fifth grade. The students should have a background on the whole numbers in order for them to fully relate or understand the topic. Let’s start the lesson by writing a 4-digit number on the board. Tell the students to read the number written in the board. Ask the students to give a four-digit number. Write it on the board. For example, the four-digit number was 1234. Tell the students to read the number. Then that should be read as it is, one thousand two hundred thirty four. Then place a dot between the two numbers.
The result would be 12. 34. Let then again the children read it. Explain the concept of decimals. Make a brief discussion on the vocabulary on decimals, about tenths, hundredths, thousandths and so on. Just for the student to have background information on the other numbers to the right of the decimal point, even if it is not necessarily needed in teaching how to round decimals to the nearest tenths. Here are definitions of a decimal. It is a real number expressed in base 10. It is composed of digits and one decimal point. Go back to the numbers you have written on the board.
The example there was 12. 34. All the digits in relation to the decimal point have a particular value. Since decimal is a base 10 number, each place has a value that is either ten times larger than the one on its right, or ten times smaller than the one on its left(“Decimal Place Value & Number Line”, 2006). Here is an illustration of the places on the right and on the left of the decimal point. You can write it on the board or you can have it done on a paper before going to the class. Practice the students reading and writing numbers that includes decimals.
Make sure to tell the students to use the word “and” after the decimal point, as for our example, twelve “and” 3 tenths 4 hundredths. Now, write a number line on the board. Let’s take 12. 34 as our example. Place the number 12. 34 on the number. This would be place between the numbers 12. 3 and 12. 4. Let’s make it clear to the students that we are talking about rounding this number to the nearest tenths so that they will know why we choose those margins. Ask the student what they notice in the number 12. 34 on the number line. Is it nearer on the left side or on the right?
Now we are ready to round off to the nearest tenths. Tell the students now to look to the place value “spot” to be rounded, that was 12. 3, the nearest tenths was 3. then look at the number next to the right. If the number is equal to five or greater than 5, then we will round UP. If it is less than 5, the number will not increase. Remember that if we round up or down, the number on the hundredths place (4), or the number next to 3 would become zero. The answer to our example if we round off to the nearest tenths would be 12. 3 since 4 is less than 5. Let the students practice it by giving other examples.
Let’s take some measurements as an example. If you have a ruler in your bag or in your table, show it to class. If they have some, then they are free to look at it. Tell them to look at the smaller lines on the side of the ruler, the centimeter side. Make it an example. A 10 centimeters is . 10 of a meter. Let’s take 1. 06m as an example. That was 1 meter and 6 centimeters. Ask the student to round to the nearest tenths and how they had decided that. The answer would be 1. 1m because the number on the right of the tenths place is 6, and it was greater than 5 so we round up.
Some other examples that they can use rounding to the nearest tenths are about money. Buying a 96-cent worth of food, then they have to round up so they will pay greater than the amount of the food. Of course they will still got change, its just for the reason that they need not look again for a 4cent on their pocket. There will be no room for errors as long as you can recognize a number equal to 5 or greater than it, then all you have to do was to round Up and the remainder becomes zero. Decimal Place Value & Number Line. (2006). Retrieved January 09, 2007, from http://www. gomath. com/htdocs/lesson/decimal_lesson1. htmSample Essay of RushEssay.com