TERM: 2^{nd} Term
WEEK: 3
CLASS: Primary 2
AGE: 7 years
DURATION: 5 periods of 40 minutes each
DATE:
SUBJECT: Mathematics
TOPIC: Addition and subtraction
SPECIFIC OBJECTIVES: At the end of the lesson, the pupils should be able to
INSTRUCTIONAL TECHNIQUES: Explanation, question and answer, demonstration, practical
INSTRUCTIONAL MATERIALS: Printed tens, bottle tops and place value table per learner,
PERIOD 1: Subtraction with borrowing
PRESENTATION  TEACHER’S ACTIVITY  PUPIL’S ACTIVITY  
STEP 1 MENTAL MATHS  The teacher begins the lesson with some mental calculations Calculate 1 11 – 2 = 2 12 – 4 = 3 12 – 7 = 4 14 – 5 = 5 12 – 5 = 6 13 – 6 = 7 13 – 8 = 8 15 – 9 = 9 12 – 5 = 10 14 – 8 =  Pupils respond and participate  
STEP 2 CONCEPT DEVELOPMENT  The teacher • Write 45 – 13 = __ on the board. • Let learners solve the problem using base ten kits. • Draw a place value table on the board and display the number 45 in it, using a base ten kit. • Ask: How would you solve this problem? • Using the diagram interactively with the class, revise the steps to solve the question 45 –13 = ___ . • Allows learners to solve this problem with you using the steps from term 1. 45 – 13 = (32) • Next, writes 45 – 17 = ___ on the board. • Draws a place value table on the board and display the number 45 in it, using your base ten kit. • Shows the learners 45 as 4 tens and 5 ones. Place them on the place value table. • Asks: What are we going to subtract from 45? (17) Yes, we will subtract 1 ten and 7 ones. • When we look at the ones place, we need to subtract 7 from 5. Is this possible? ( No) How do you think we could solve this? Let the learners discuss options. • We will borrow 1 ten and exchange it for 10 ones. So now we have 10 + 5 = 15 ones. • Now we can subtract. We get 15 – 7 = 8 • Remember we borrowed 1 ten from 4 tens, so we are left with 3 tens. Now we subtract 1 ten from 3 tens; 30 – 10 = 20. • Ask: What is the answer? 45 – 17 = (28)
CLASS ACTIVITY The teacher • Keeps the number sentence 45 – 17 = 28 on the board • Lets learners solve this problem using expanded notation. (Notice how 45 is broken into 30 + 15.) 45 – 17 = 30 + 15 – 10 – 7 = (30 – 10) + (15 – 7) = 20 + 8 = 28 • Asks: how is this similar to the working we did in the place value table? (The same answer. Doing subtraction in the same places.) • Discusses that this is a different strategy used to solve the same subtraction problem. • We will now solve the same problem using the column method.
O: 15 – 7 = 8 T: 30 – 10 = 20 • Solves this problem with the learners, discussing it in the following way: We start in the ones place. Ask: Can we subtract 7 from 5? ( No) What should we do? We borrow 1 ten from the tens place which gives us 15 ones in the ones place so we can say 15 – 7 = 8. We write 8 in the ones place. We borrowed 1 ten from 4 tens so there are 3 tens left in the tens place. We subtract 1 ten from 3 tens; so we get 30 – 10 = 20. Write 2 in the tens place. The answer is 28. It is very important that the learners understand the concept of exchanging 1 ten for 10 ones. • Asks: How is this similar to the working we did in the place value table? (The same answer. The same movement in each place.) • Discusses that this is a different strategy for solving the same subtraction problem.  Pupils pay attention and participate  
STEP 3 CLASSWORK  NOTE: While the learners are solving these problems walk around the class. Assist those who may be struggling with the column method and carrying the ten. Learners should be using their base ten kits in the place value table which they drew into their classwork books. Help them to make the connection between the manipulation they do with the base ten kits and the numeric recording they write in their books. The solutions are shown below. Calculate using a place value table and the column method. a 63 – 26 = __ b 71 – 47 = __ c 97 – 38 = __ (59)
 Pupils attempt their class work  
STEP 4 HOMEWORK  Calculate using a place value table and the column method. 90 – 88 =  The pupils writes it in their homework book  
STEP 5 SUMMARY  The teacher summarizes by reminding the pupils that in this lesson we solved subtraction problems with borrowing. We solved subtraction problems using the place value table and the column method.
She marks their class works, makes corrections where necessary and commends them positively 

PERIOD 2: Practising subtraction with borrowing
PRESENTATION  TEACHER’S ACTIVITY  PUPIL’S ACTIVITY  
STEP 1 MENTAL MATHS  The teacher begins the lesson with some mental calculations Calculate 1 15 – 8 = 2 15 – 9 = 3 17 – 8 = 4 18 – 9 = 5 16 – 7 = 6 16 – 9 = 7 17 – 9 = 8 15 – 6 = 9 15 – 7 = 10 16 – 8 =  Pupils respond and participate  
STEP 2 CONCEPT DEVELOPMENT  The teacher • Writes 53 – 27 = __ (26) on the board. • Refers to the previous lesson (lesson 11) for guidance. • Lets learners solve this problem using their base ten kit in a place value table, expanded notation and the column method. • Selects different learners to come to the board to show how to solve this problem using the different strategies. • Discusses the relationship between the strategies with the learners to help them make the connections between them. This will deepen their understanding of how to subtract.
CLASS ACTIVITY The teacher • In this activity we will be showing the learners the relationship between subtraction and addition as inverse operations. • Keeps the number sentence 53 – 27 = 26 on the board. • Asks: Can you think about how we could check if this answer is correct or not? (Using addition.) • Asks: How would the addition look: 53 + 27 = OR 27 + 26 = OR 53 + 26 = ? (27 +26/26 + 27) • Discusses with learners why 27 + 26/26 + 27 is correct. (27 + 26 or 26 + 27 are correct because they give the answer of 53. The other number sentences, 53 + 27 = and 52 + 26 = , reach a different answer. We need to work with the same three numbers that we had in the subtraction number sentence.) • It is helpful to remind learners the partpartwhole diagram (which is like a bond table) to find the correct addition. • Writes 27 + 26 = __ on the board. • Uses the column method to solve this problem with the learners.
O: 7 + 6 = 13 T : 20 + 20 = 40 So, the answer 26 is correct. • Discusses with the learners that we can use addition to check the answer of our subtraction problems.  Pupils pay attention and participate  
STEP 3 CLASSWORK  NOTE: While the learners are solving these problems walk around the class. Assist those who may be struggling with the column method and carrying and borrowing the tens. Learners should be using their base ten kits in the place value table which they drew into their classwork books. Help them to make the connection between the manipulation they do with the base ten kits and the numeric recording they write in their books. The solutions are shown below. Calculate using the column method and check your answer using addition. a 82 – 45 = __ b 71 – 27 = __ c 60 – 34 = __
Solutions for the checking process: Check the answer using addition. a (45 + 37 = 82) b (44 + 27 = 71) c (26 + 34 = 60) (The order of numbers in the addition does not matter. a) 37+45; b) 27+44; c) 34+26 are also fine.)  Pupils attempt their class work  
STEP 4 HOMEWORK  Calculate using the column method and check your answer using addition. a 35 – 9 = __ b 90 – 8 = __
Solutions for the checking process: Check the answer. (The order does not matter – they can also add 9 + 26 and 8 + 82) a (26 + 9 = 35) b (82 + 8 = 90)
 The pupils writes it in their homework book  
STEP 5 SUMMARY  The teacher summarizes by reminding the pupils that in this lesson we solved subtraction problems with borrowing. We checked our subtraction answers using addition.
She marks their class works, makes corrections where necessary and commends them positively 

PERIOD 3: Subtraction with borrowing on a number line
PRESENTATION  TEACHER’S ACTIVITY  PUPIL’S ACTIVITY 
STEP 1 MENTAL MATHS  The teacher begins the lesson with some mental calculations Calculate 1 3 – 1 = 2 4 – 2 = 3 5 – 2 = 4 6 – 3 = 5 7 – 2 = 6 7 – 4 = 7 8 – 5 = 8 8 – 2 = 9 9 – 7 = 10 9 – 5 =  Pupils respond and participate 
STEP 2 CONCEPT DEVELOPMENT  The teacher • Write the following on the board. • Allow the learners to work in pairs to solve these problems mentally. 1 20 – 10 = 2 50 – 30 = 3 60 – 10 = 4 70 – 30 = 5 80 – 70 = 6 50 – 40 = 7 80 – 60 = 8 90 – 40 = 9 70 – 10 = 10 90 – 60 = • If learners struggle to do subtraction mentally, give them tips for doing mental calculation for these 10 problems: They could say (21) tens, (53) tens, (61) tens, (73) tens, (87) tens … reminding them how they worked with baseten kit. • Discusses the answers as a class.
CLASS ACTIVITY The teacher • Writes the following on the board: 42 – 9 = __ (33) 42 – 9 = (33) • Draws the number line (shown above) • Asks the learners: Which multiple of 10 is 42 closest to? (40) • Asks: If we jump to 40 on the number line. How much have we subtracted? (2) • Asks: How many do we still have to subtract? (7) 40 – 7 = 33. Draw the jump on the number line. The answer is 33. • Repeats this activity using 71 – 65 = (6) and 93 – 48 = (45). • Let the learners guide you and draw the number lines.
ACTIVITY II • We will now check our answers from activity 2 using the column method. • Solve 42 – 9 = (33), 71 – 64 = (7) and 93 – 48 = (45) using the column method in the same way that you have done in previous lessons.  Pupils pay attention and participate 
STEP 3 CLASSWORK  Solve using a number line. 1 30 – 7 = __ 2 95 – 26 = __ 3 78 – 19 = __ 4 81 – 6 = __ 5 60 – 22 = __ 6 92 – 84 = __
 Pupils attempt their class work 
STEP 4 HOMEWORK  Solve using a number line. 1 63 – 26 = __ 2 77 – 47 = __  The pupils writes it in their homework book 
STEP 5 SUMMARY  The teacher summarizes by reminding the pupils that in this lesson we have solved subtraction problems with borrowing using a number line. We checked our answers using the column method.
She marks their class works, makes corrections where necessary and commends them positively 

PERIOD 4: Assessment
PRESENTATION  TEACHER’S ACTIVITY  PUPIL’S ACTIVITY 
STEP 1 ORAL ASSESSMENTS  The teacher asks questions on mental maths treated so far  Pupils respond and participate 
STEP 2 DISCUSSION  The teacher discusses all the methods used by some learners in the oral assessments(some of the questions are solved on the board by the learners) and addresses any misconceptions that may have risen  Pupils pay attention and participate 
STEP 3 WRITTEN ASSESSMENTS  1 Calculate 92 – 38 = __ using a base ten kit and place value table. 2 Use the column method to check your answer to 92 – 38 = __. 3 Solve 64 – 26 = __ (38) using a number line. 4 Use column addition to check your answer to 64 – 26 = __.  Pupils attempt their class work 
STEP 4 SUMMARY  The teacher marks the written assessments, corrects were necessary and commends the pupils 

PERIOD 5: Weekly Test/consolidations
TEACHER’S ACTIVITY: The teacher revises all the concepts treated from period 14 and gives the pupils follow through exercises, quiz and tests. She marks the exercises, makes corrections and commends the pupils positively.
PUPIL’S ACTIVITY: The pupils work on the worksheets and exercises give by the teacher individually
CONSOLIDATION
1 Solve 85 – 37 = ___ using a number line.
2 Solve 81 – 16 = ___ using the column method.
3 Use addition to check your answer to 81 – 16 = ___.
4 Solve 83 – 25 = ___ using a base ten kit and a place value table.
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