Exercise 1

1. 2. 3. 4. 5. 6. 7.

Exercise 2

1. 2. 3. 4. 5. 6.

7.

There are 1,344 sheets of paper altogether

5,852 pencils

$31,500 is his annual salary.

Total cost for 15 chairs and 30 tables is $59,280. The company sent a total 32,382 advertisements. There are 1440 minutes in a day.

There are1,416 chairs in the hall.

There are 15 plates.

His monthly salary is $1,575.

There are 411 apples in each basket. 376

Each student contributed $110. a) 45 boxes b) 4 donuts were left over.

There are 5 motorbikes in the car park.

Hello pupils,

How are you? I trust that all is well with you! Last week we solved worded mathematical problems that involved multiplication and division operations. This week, we will be examining the concept of decimals. Let’s begin!

Decimals

What are decimals? I’m sure you heard the term before. If not, do not worry. Let’s find out what decimals are.

Decimals are numbers which consist of two parts namely, a whole number part and a fractional part separated by a decimal point.

For example: The number 49.15 is a decimal number.

Decimal Place Value Chart

The decimal place value chart below shows the place values of the digits in a given decimal number.

In the example we looked at earlier, we say that 49.15 is a decimal number. If we use the decimal place value chart above, we will see that the decimal number 49.15 has 4 tens, 9 ones, 1 tenth, and 5 hundredths.

Let us practice writing the value of digits in various decimal numbers.

Exercise 1

Write the value of the underlined digit. a. 322.143 b. 65.98 c. 2.6 d. 764.987 e. 52.9 f. 32.99

Excellent work, boys and girls!

Below, is another exercise for you to complete. The first one is done for you as an example:

Exercise 2

Write the following in expanded notation. a) 423.3 = (4 x100) + (2x10) + (3x1) + (3x ) b) 82.5 c) 623.6 d) 932.1 e) 78.2 f) 26.22 g) 564.1 h) 2.3

Great job, students! Let’s now do the reverse of what we just did!

Exercise 3

Write the numeral of the following: a) (2x100) + (3x10)+ (4x1) + (4 x ) b) (3x 100) + (2 x 10) + (9x1) + (2 x ) c) (5 x1000) + ( 3x 100) + (2x10) + (2x1) + (9 x ) d) (2 x1000) + (5 x100) + ( 9x 10) + (5x1) + (3 x ) e) (5 x1000) + (3 x 100) + (3x 10) + (2x1) + (9 x ) f) (1 x1000) + (4 x 100) + ( 3x 10) + (2x1) + (9 x ) g) Great job, students! I am proud of you!

As our final sub-topic for today, let us look at the approximation of decimals to whole numbers:

Approximating decimals to whole numbers

Boys and girls, do you know what it means to approximate?

An approximation in Mathematics is an estimation of a number or rounding a number to its nearest place value.

When rounding off decimals to the nearest whole number we have to examine two steps:

Step 1- If the tenths digit is less than five (1,2,3,4) whole number.

Step 2- If the tenths digit is greater than four (5,6,7,8,9) to the whole number.

do not add one to the add one (round up)

Let us examine two examples:

Example 1:

16.2 approximated to the nearest whole number is 16. This is so because if we examine the digit in the tenths place (2), it is less than five, so we do not add one to the whole number. We leave it as it is.

Example 2:

21.7 approximated to the nearest whole number is 22. This is so because if we examine the digit in the tenths place (7), it is greater than four, so we add one (round up) to the whole number. Hence, 1 added to 21 becomes 22.

Practice working the following:

Exercise 4

Approximate to the nearest whole number: a) 8.9 b) 24.67 c) 34.2 d) 53.45 e) 44.99 f) 58.7 g) 12.1 h) 36.5

That’s all for today, boys and girls. What have you learned? I hope you have learned a lot! Thank you for being receptive. Check back next week for the answers to this week’s problems. Have a productive week ahead, Bye!