Estimation Basic 4 Mathematics Lesson Note

LEARNING AREA

1. Round Whole Numbers to 10 and 100
2. Round Decimal Numbers to the Nearest Whole Numbers
3. Sum and Difference of Estimated Numbers

PERFORMANCE OBJECTIVES By the end of the lesson, the pupils should have attained the following objectives (cognitive, affective and psychomotor) and should be able to –

1. round whole numbers to the nearest 10 and 100.
2. round decimals to the nearest whole numbers.
3. estimate the sums and differences of whole numbers and decimals.
4. Estimating the product of two numbers solves word problems involving estimation.

ENTRY BEHAVIOUR

INSTRUCTIONAL MATERIALS The teacher will teach the lesson with the aid of charts on estimation.

METHOD OF TEACHING – Choose a suitable and appropriate methods for the lessons.

Note – Irrespective of choosing methods of teaching, always introduce an activities that will arouse pupil’s interest or lead them to the lessons.

REFERENCE MATERIALS

1. Scheme of Work
2. 9 – Years Basic Education Curriculum
3. Course Book
4. All Relevant Material
5. Online Information

CONTENT OF THE LESSON

LESSON ONE – INTRODUCTION

Pupil’s Activities 1 – Rounding to the nearest 10

Teacher’s remark – 30 59 34 46 67 and 78 are 50. Each of these numbers are multiples of 10 and each number has zero in its unit place. These numbers (i.e. multiples of 10) are round numbers. 11 12 13 14 15 16 17 18 19 are closer to 10 and 21 22 23 24 are closer to 20. We normally rounded downward their digits in tens and units place. Numbers from 1 to 4 in the unit place are rounded down while numbers from 5 to 9 in the unit place are rounded up.

The middle number is greater than (5) 22 – 5)

It is rounded to 10 from 5:

Therefore, 5 is rounded to 10 to the nearest 10.

1. Rounding rounded numbers between 26 and 30.

Therefore, 26 is rounded to 30 to the nearest 10.

Pupil’s Activities 2 – Extension Data Views

Round these Numbers to the Nearest 10

1. 12
2. 85
3. 97
4. 108
5. 555

LESSON TWO – ROUNDING TO THE NEAREST 100

Pupil’s Activities 1

Teacher’s remark – 550 is nearer to 600 than to 700. Therefore, 550 is rounded to 600 to the nearest 100.

Pupil’s Activities 2 – Extension Data Views

Round these numbers to the nearest 100.

1. 289
2. 345
3. 432
4. 731
5. 890

LESSON THREE – ROUNDING DECIMALS TO NEAREST WHOLE NUMBERS

Teacher’s/Pupil’s Activities 1

Teacher’s remark – Decimals can also be rounded to the nearest whole numbers with and without using a number line. For eg 5.2 is nearer rounded number between 5 and 6. 5.2 is rounded to 5 (the nearest whole number).

Pupil’s Activities 2 – Working Examples

Round to the nearest whole number:

1. 3.52

14.7 is middle number between 15 and 15

Therefore, rounded to 15.

3.2 is closer 5 than 1

Therefore, rounded to 5.

1. 5.06

6.8 is closer to 7 than 7

Therefore, rounded to 7.

Pupil’s Activities 3 – Extension Data Views

Round these to the nearest whole number:

1. 5.94
2. 7.08
3. 2.56
4. 4.18
5. 7.75

LESSON FOUR – ESTIMATING SUMS AND DIFFERENCES OF WHOLE NUMBERS

Teacher’s/Pupil’s Activities 1 – Estimating Sums of Whole Numbers

Working Examples:

5 + 7 = 12

8.1 + 7.9 (nearest 10)

8 + 8 = 16 (nearest 10)

15.5 + 31.9

The difference is 43.

2: 369 + 457

3.69 = 4 (3.5 (nearest 100)

4.57 = 5 (4.5 (nearest 100)

4 + 5 = 9

7 = 9 + 5 = 2

The difference is 28.

Teacher’s/Pupil’s Activities 2 – Estimating Differences of Whole Numbers

Working Examples:

5.76 = 58

58 = 58 (nearest 10)

76 = 80 (nearest 10)

4.5 = 5.13 (nearest 10)

5.6 = 7.9

The difference is 21.

2: 809 – 395

8.09 = 8 (8.1) (nearest 100)

3.95 = 4 (4.05 (nearest 100)

8 – 4 = 4

4 (1.2 – 0.58)

The difference is 414.

Pupil’s Activities 3 – Extension Data Views

Estimate the following:

1. 57 + 43
2. 84 – 47
3. 395 + 782
4. 869 + 563

LESSON FIVE – ESTIMATING SUMS AND DIFFERENCES OF DECIMAL NUMBERS

Teacher’s/Pupil’s Activities 1 – Estimate Sums

Estimate the following to the nearest whole number and simplify.

1: 5.94 + 2.07

5.94 = 6 (nearest whole numbers)

2.07 = 2 (nearest whole numbers)

6 + 2 = 8

The difference is 8.00.

2: 50.2 + 10.9

50.2 = 50 (nearest whole numbers)

10.9 = 11 (nearest whole numbers)

50 + 11 = 61

The difference is 61.

Teacher’s/Pupil’s Activities 2 – Estimate Differences

Working Examples:

26.9 – 15.3

23.9 = 24

15.3 = 15

24 – 15 = 9

2: 4.125 – 1.56

4.125 = 4

1.56 = 2

4 – 2 = 2

3: 60 – 8

Pupil’s Activities 3 – Extension Data Views

Estimate the following to the nearest whole number and simplify.

1. 0.347 + 28.56
2. 8.752 + 6
3. 6.431 – 3e.46
4. 26 – 4.269

LESSON SIX – EXTRA CLASS/QUANTITATIVE REASONING

This Class – Estimating the product of two numbers. Follow the same procedures.

Quantitative Reasoning – As stated in the pupils’ quantitative books or textbooks.

PRESENTATION

To deliver the lesson, the teacher adopts the following steps:

1. To introduce the lesson, the teacher revises the previous lesson. Based on this, he/she asks the pupils some questions.
2. Guides pupils to find estimate of sum and product of numbers.

Pupil’s Activities – Estimate sums and products of numbers.

CONCLUSION

To conclude the lesson for the week, the teacher revises the entire lesson and links it to the following week’s lesson.

LESSON EVALUATION

Pupils to:

1. estimate the sum and product of numbers, heights, weights and solids when and explain the ideas.
2. use estimating involving sum and product of numbers.