LESSON PLANNING OF SUBTRACTION OF 2-DIGIT NUMBERS (WITH BORROWING) COMMUTATIVE PROPERTY

Subject Mathematics

Grade 2^{nd}

Students` Learning Outcomes

- Subtract ones from 2-digit numbers with borrowing.

Information for Teachers

- Students already know about subtraction, how to write subtraction equation and word problem related to subtraction without borrowing.

Subtraction Equation

Subtraction word problem

- Subtraction means how bigger one thing is than the other.

- In this session they will understand subtraction with borrowing.
- Borrowing: if one of the columns has a smaller number on top, the number on top borrows from the number to its left.

- To borrow means to take something that is not really yours.
- While teaching the lesson, the teacher should also consult textbook at all the steps where and when applicable.

Material / Resources

Writing board, chalk / marker, duster, match sticks, rubber bands, empty match boxes, stones / pebbles, and number flashcards

Introduction

- Give some subtraction questions to students to solve e.g. 9 – 6, 8 – 7, 7 – 4, etc.

- Remind them that for the question 7 – 4, they first have to count and take out 7 fingers and then they have to close 4 fingers one by one. Count the remaining fingers, it is the answer.

Give to the students some word problem related to subtraction to solve as such; Ali has 7 sweets. If he gives 2 to his sister, how many are left with him?

Development

Activity 1

- Repeat some simple subtraction sums, without carrying, to refresh students` learning of subtraction from last year.

- For this purpose make students do at least 5 questions on the board.

Activity 2

- Give a situation such as; if you have 12 (bundle of 10 and 2 loose sticks) matchsticks and your best friend wants 4 match sticks, how many match sticks will be left with you after sharing?
- Discuss the situation and guide them to write a subtraction question (ones from two-digit number with borrowing) on writing board as such; 12 – 4.

- Give match sticks to students in group and ask them to represent given number by showing with a bundle of 10 sticks and two loose sticks.
- Ask students, can we takeaway 4 loose sticks from 2? (Remind them rule: units to be subtracted from units)
- Ask students about possible way to takeaway 4 from 2.
- After discussion borrow one 10 at unit place, to turn the 2 into 12.
- Remind students to count forward from 4 to 12 on their fingers tips. So, this way they will take away 4 from 12 ones to get a difference of 8.
- Show into board like we borrowed 10 and it makes 12 units, 80 we can subtract 4 from 12.
- Repeat the same activity for other questions.

Activity 3

- Write a subtraction question (1-digit number from 2-digit number with borrowing) on board, as such; 25 – 6.

- Give a number tray made up of empty match boxes along with stones / pebbles as shown in the figure.

- Ask students to represent first number that is 25 with stones / pebbles.

- Ask students can you take away 6 from 5?
- Discuss how to take away 6 from 5, borrow one stone from ten to get 10 ones, then takeaway 6 ones from 15.
- Count and write stones in unit and tens to find the difference. (19)
- Repeat the same activity for other questions.

Activity 4

- Put a pile of 2-digit number flashcards on your desk.

- Ask every student to pick any one card at random to get a 2-digit number.
- Ask them to take away 9 from drawn number and find the difference.
- Ask few volunteer students to come up to the board and solve their question.

Sum up / Conclusion

- Borrowing means taking from next higher place.
- Borrowing is always in 10, this 10 is added to the number which borrows.

- Maximum number after borrowing could be 19.
- Write some subtraction question (1-digit number from 2-digit number with borrowing) on board and solve with the help f students and explain process of borrowing.

Assessment

- Give some question to subtract 1-digit number from 2-digit number with borrowing.

- Give students two dice to roll and get double digit number. Ask them to takeaway 9 from the drawn number and find difference.

Follow up

- Ask them to write any five questions of subtraction (ones from 2-digit number) by your own and solve at home.

- Ask the students to solve the questions given in their textbook.

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