Post by Wangechi Ngunjiri gechi09 on Jun 8, 2009 16:39:31 GMT -5
Date: 30th March, 2009
Subject: Mathematics
Topic: Subtraction of decimals
Grade: Three
Age: 8-9 year olds
Ability: Mixed
Number of Students: 19
Number of males: 8
Number of females: 11
Time: 45 minutes
Objectives: At the end of the lesson, students should be able to:
• Read numbers.
• Identify equivalent decimals.
• Subtract decimals.
Materials: Charts, chalkboard.
Previous knowledge:
• Students know how to add decimals.
• Students know how to regroup when subtracting.
Introduction:
Students will sing a song about decimals.
“When you need to add a decimal
Line up the dot,
Then all your values will be
In the right spot.
So line up all you’ve got.
Drop the decimal into your difference or sum.
It’s the same for addition as it is subtraction.
Line it up and drop it, forget about it.
Now work the problem carefully
And know that your enemy is speed
Yeah, work the problem carefully
Slow down…”
Procedure:
Step 1:
Teacher will introduce topic and tell students they will be subtracting decimals. Teacher will show students that the decimal point always separates the ones and tenths and will ensure that all students can read the decimals. For example, 26.56 is twenty-six and fifty-six hundredths.
Step 2:
Teacher will present chart with the main points that students should follow when subtracting decimals:
• The most important thing to remember when subtracting decimals is to line up all the decimal points in a column.
• To subtract a small decimal number from a larger decimal number, write them down with the larger one on top and the decimal points underneath one another.
• If the number does not have the same number of digits to the right of the decimal point, you will still line up the decimal points and fill the empty place values with zeros.
Teacher will then show students how placing zeros before the left most digit does not change the number’s value. Teacher will also explain and illustrate equivalent decimals. For example, 0.4 = 0.40. Teacher will show strategies on a chart as well.
Step 3:
Teacher will then show students on the board how to subtract the decimals by starting from the right, and subtracting each column in turn. Teacher will remind students that they are to borrow a digit from the next column to the left if the number they are subtracting is bigger than the number they are subtracting from. Teacher will then work out a few examples.
Closure:
With the use of a chart, teacher will go over the main points that were taught in the lesson.
Application:
Students will complete a work sheet.
1. 0.7 – 0.3 =
2. 27.583 – 0.2 =
3. 2.37 – 0.031 =
4. 438.0 – 417.9 =
5. On Monday morning, the school cafeteria had 5.44 gallons of milk. At lunch, the students drank 4.41 gallons of the milk. How much milk does the cafeteria have left?
Evaluation:
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Subject: Mathematics
Topic: Subtraction of decimals
Grade: Three
Age: 8-9 year olds
Ability: Mixed
Number of Students: 19
Number of males: 8
Number of females: 11
Time: 45 minutes
Objectives: At the end of the lesson, students should be able to:
• Read numbers.
• Identify equivalent decimals.
• Subtract decimals.
Materials: Charts, chalkboard.
Previous knowledge:
• Students know how to add decimals.
• Students know how to regroup when subtracting.
Introduction:
Students will sing a song about decimals.
“When you need to add a decimal
Line up the dot,
Then all your values will be
In the right spot.
So line up all you’ve got.
Drop the decimal into your difference or sum.
It’s the same for addition as it is subtraction.
Line it up and drop it, forget about it.
Now work the problem carefully
And know that your enemy is speed
Yeah, work the problem carefully
Slow down…”
Procedure:
Step 1:
Teacher will introduce topic and tell students they will be subtracting decimals. Teacher will show students that the decimal point always separates the ones and tenths and will ensure that all students can read the decimals. For example, 26.56 is twenty-six and fifty-six hundredths.
Step 2:
Teacher will present chart with the main points that students should follow when subtracting decimals:
• The most important thing to remember when subtracting decimals is to line up all the decimal points in a column.
• To subtract a small decimal number from a larger decimal number, write them down with the larger one on top and the decimal points underneath one another.
• If the number does not have the same number of digits to the right of the decimal point, you will still line up the decimal points and fill the empty place values with zeros.
Teacher will then show students how placing zeros before the left most digit does not change the number’s value. Teacher will also explain and illustrate equivalent decimals. For example, 0.4 = 0.40. Teacher will show strategies on a chart as well.
Step 3:
Teacher will then show students on the board how to subtract the decimals by starting from the right, and subtracting each column in turn. Teacher will remind students that they are to borrow a digit from the next column to the left if the number they are subtracting is bigger than the number they are subtracting from. Teacher will then work out a few examples.
Closure:
With the use of a chart, teacher will go over the main points that were taught in the lesson.
Application:
Students will complete a work sheet.
1. 0.7 – 0.3 =
2. 27.583 – 0.2 =
3. 2.37 – 0.031 =
4. 438.0 – 417.9 =
5. On Monday morning, the school cafeteria had 5.44 gallons of milk. At lunch, the students drank 4.41 gallons of the milk. How much milk does the cafeteria have left?
Evaluation:
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________