CAPS baseline framework
Lesson 36: Word problems
Teacher’s notes
This lesson is one of the fully planned lessons to be used to cover the Term 1 curriculum CAPS topics: 1.6 Problem-solving techniques, 1.7 Addition and subtraction, 1.12 Techniques (methods or strategies) 1.13 Addition and subtraction
Lesson Objective: To solve addition and subtraction problems using bar diagrams.
Lesson Vocabulary: add, subtract, bar diagram Resources: n/a
Date: Week Day
1 MENTAL MATHS (10 MINUTES)
Calculate Answer Calculate Answer
1 1 + 15 = ______ 16 6 3 + 35 = ______ 38 2 2 + 25 = ______ 27 7 1 + 42 = ______ 43 3 3 + 19 = ______ 22 8 2 + 55 = ______ 57 4 4 + 45 = ______ 49 9 4 + 65 = ______ 69 5 5 + 78 = ______ 83 10 4 + 78 = ______ 82 2 LESSON CONTENT – CONCEPT DEVELOPMENT (45 MINUTES)
In this lesson learners will use a bar diagram to help them solve addition and subtraction problems. The bar diagrams will be used to represent information. We will solve word problems that involve change and combine. These will be explained during the lesson.
Today we are solving addition problems using bar diagrams.
Activity 1: Whole class activity
• Write the problem 348 +26 = ____ on the board.
• Ask learners to each solve the problem in their classwork books, using simplified pictorials.
Lesson 36: Word problems
WEEK 8
H T O
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3 7 4
• Ask learners to tell the person sitting next to them about how they solved the problem using the column method.
• Walk around the class listening to the conversations, and clearing up any misconceptions you may overhear.
• Ask a learner to show the column method on the board.
• Encourage the learner to verbalise their strategy as s/he writes on the board.
• Ask questions such as: Did you have to carry 10 tens or 10 ones? Did you have to borrow 10 tens or 10 ones? Why not? What do we do with the number in the hundreds column when we don’t have anything to add to it / subtract from it?
• Repeat with the following problems:
• 59 + 407 = ____
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4 6 6
• 941 – 22 = ____
H T O
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9 1 9
• 736 – 27 = ____
H T O
£££££
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• Ask questions such as: Did you have to carry 10 tens or 10 ones? Did you have to borrow 10 tens or 10 ones? Why not? What do we do with the number in the hundreds column when we don’t have anything to add to it / subtract from it? What happens when there is a zero?
Activity 2: Whole class activity
• Write the following word problem on the board.
• There are 129 sweets in the jar. Zanele puts in another 47 sweets. How many sweets are in the jar now?
• The first step is to understand the question properly.
• In step 1, we write the word problem on the board. Next, we read the problem. Then, we let the learners read the problem themselves in order to understand the problem.
• After that we underline the numbers. These are 129 and 47.
• Find the question and draw wavy line under the question. (How many sweets are in the jar now?)
• Draw the following diagram on the board:
129 sweets
? sweets
47 sweets
• Ask the learners what they think the number sentence should be. Let learners discuss with the person sitting next to them.
• Ask a learner to come up to the board to write the number sentence (129 + 47 = ___).
Ask the learner to explain how s/he worked out what the number sentence should be.
• Allow learners time to solve the problem.
• Discuss the answer with the learners (176 sweets). Ask learners to explain how they solved the problem.
• There are 129 sweets in the jar. Zanele puts in another 47 sweets. That means the number of sweets increases/ there should be more sweets than the beginning. So I did addition/ I add 47 to 129. There are 176 sweets in the jar.
• This is an example of an addition problem (change).
Activity 3: Whole class activity
• Write the following word problem on the board.
• There are 267 children on the field. 39 children go back to their classrooms. How many children are on the field now?
• The first step is to understand the question properly.
• After that we underline the numbers. These are 267 and 39.
• Find the question and draw wavy line under the question. (How many children are on the field now?)
Lesson 36: Word problems
WEEK 8
• Draw the following diagram on the board
? 267 children
39
• Ask the learners what they think the number sentence should be. Let learners discuss with the person sitting next to them.
• Ask a learner to come up to the board to write the number sentence (267 – 39 =). Ask the learner to explain how s/he worked out what the number sentence should be.
• Allow learners time to solve the problem.
• Discuss the answer with the learners (228 children). Ask learners to explain how they solved the problem.
• There are 267 children on the field. 39 children go back to their classrooms. 39 children disappear from the field. They are not on the field anymore. So I did subtraction/I take away 39 from 267. There are 228 children left on the field.
• This is an example of a subtraction problem (change).
3 CLASSWORK ACTIVITY AND CORRECTION OF HOMEWORK (25 MINUTES) Note: This classwork should be done as a class so that you and the learners can discuss and solve the problems together. You always follow the steps to solve word problems as to write the word problem on the board, to read the problem, to let the learners read the problem themselves in order to understand the problem. After that we underline the numbers and draw wavy line under the question.
You are going to draw the bar diagrams on the board to help the learners solve the problems. Make sure you ask learners to explain how they solved the number sentences.
Learners need to be able to explain their strategies to the class or to the person sitting next to them.
Solve the word problems using a bar diagram:
a The teacher has 342 pencils. The shop down the road gives her 69 more. How many pencils does she have now? (change)
342 pencils
? pencils
69 pencils
342 + 69 = 411 (Learners may calculate with the strategy that they feel comfortable with).
(The teacher has 411 pencils)
b Thembi picks up 543 shells. 29 were broken. How many unbroken shells does Thembi have? (combine)
? unbroken shells 543 shells
29 unbroken shells
543 – 29 = 514 (Learners may calculate with the strategy that they feel comfortable.) (Thembi has 514 unbroken shells.)
4 HOMEWORK ACTIVITY (5 MINUTES)
Draw a bar diagram to show the following addition problem.
Silo picks up 264 pieces of litter. He then picks up another 17 pieces of litter. How many pieces of litter did Silo pick up altogether?
264 pieces
? pieces altogether
17 pieces
264 + 17 = 281
(Silo picked up 281 pieces of litter)
5 REFLECTION AND SUMMARY OF LESSON (5 MINUTES)
Call the whole class to attention and summarise the key concepts of the lesson:
Today we have solved word problems. We solved addition word problems using change, compare and combine.