LESSON PLANNING OF SOLVE REAL WORD PROBLEMS OF SUBTRACTION (WITHOUT BORROW)

Subject Mathematics

Grade 2^{nd}

Students` Learning Outcomes

- Subtract 3-digit numbers from 3-digit number without borrow.
- Solve real life problems of subtraction without borrow.

Information for Teachers

- Subtraction is one of the four basic arithmetic operations;

- it is the inverse of addition.

General equation of subtraction is c – b = a where c > b.

- List the key words for subtraction; subtract, minus, decrease, less than, take away, reduce etc. on chart paper and display in the class.

How to make a number tray:

- Use empty match boxes as trays and pebbles as digits, join 3 match boxes with each other to make a number tray.

- Then Take first box as unit, second as tens and third as hundred.

- While teaching the lesson, the teacher should also consult with textbook at all steps where and when applicable.

Material / Resources

Writing board, chalk / marker, duster, number tray, counting frame, pebbles / beads

Introduction

- Discuss with students that they already know how to subtract 1-digit and 2-digit numbers from 3-digit numbers.

- Now we will apply that knowledge to solve the word problems.
- First give students few sums to revise the subtraction concept.
- Write the numbers in column headings; hundred, tens, and unit.

- Subtract one column at a time.
- Solve the questions from right to left.

Development

Activity 1

- Give number try made up of empty match boxes along with some pebbles in groups.

- Write a three digit number on writing board (e.g. 235) and ask the students to represent number by putting pebbles in appropriate part of tray.

- Now write a 3-digit number (e.g. 123) and ask students to take away amount from material they presented on number tray. Ask the answer from the groups on the basis of material left in the number tray.
- Repeat activity for other numbers.

Activity 2

- Give counting frame along with some beads in groups.
- Write a three digit number 635 on writing board (minuend) and ask students to represent number by inserting beads in appropriate column strings.
- Write a 3-digit number 321 and ask the students to take away it from the given number by using counting frame.
- Ask the number of beads left in unit, tens and hundred, 314 is the answer of subtraction questions.
- Repeat activity for other numbers.

Activity 3

- Provide following worksheet (with different subtraction word problems) to the students in group and ask them to complete.

- Make worksheets with different questions for each group. Other examples for real-life situations:

- Take worksheet and interchange with other groups for peer assessment.
- Discuss the work with students, their difficulties, common errors and mistakes. Appreciate the groups for their working.

Activity 4

- Ask the students to solve the questions given in their textbook.
- Observe their work and guide them where necessary.

- Assign some questions to the students as homework from textbook.

Sum up / Conclusion

- Subtraction is easy process if we mind the place value.
- Word problems are application of subtraction questions.
- Word problems are part of our daily life.
- Give three statement questions to students to solve e.g. Sara got 8 candies. She gave 3 other friend. How many candies left with Sara etc.?
- List down key words (subtract, minus, decrease, difference, less than, take away, fewer than, reduce) which identify the operation of subtraction in the problem.

Assessment

- Write some subtraction questions on writing board (3 from 3-digit without borrowing) e.g. 456 – 123 and ask students to solve the question on their notebooks.
- Put statement questions strips in a box related to subtraction. Ask students to draw two strips from the box, solve them and return back each. E.g. there are 9 pencils in a holder, Ali took 2 pencils, and how many are left in the holder?

Follow up

- Assign few subtraction questions to solve (3-digit from 3-digit without borrowing) as homework

- Ask students to find a situation from daily life where they used the concept of subtraction e.g. Mother made 3 chapattis, my sister ate 1, how many are left?
- Also ask them to explain how they will solve the questions where bigger numbers are involved?