## Whole Numbers and Basic Operations

 1.1 Let's Learn to Use a Calculator
Parts of Calculator
• On Button is used to switch on the calculator.
• Number buttons are used to type in the numbers.
• Operation buttons are used to type in the operations.
• Make sure to do the multiplication and division operation first before addition and subtraction operations.
Steps in Using a Calculator

Calculate the number given using a calculator.

$$752\ 168+85\ 479\ =$$

• Press the on button
• Press the buttons 7 5 2 1 6 8 +
• Press the buttons 8 5 4 7 9
• Press the = button. The screen displays the answer 837647. The sign ' means leave a space between the digits.

Calculation involving Division

$$235\ 620-1\ 740\ \div60\ =$$

 STEP 1 STEP 2 Press the on button Press the buttons 1 7 4 0 ÷ Press the buttons 60 Press the = button. The screen displays the answer 29 Press the on button Press the buttons 2 3 5 6 2 0 - Press the buttons 2 9 Press the = button. The answer displays the answer 235 591

Calculation involving Multiplication

$$98\ 130+675\times14\ =$$

 STEP 1 STEP 2 Press the on button Press the buttons 6 7 5 x Press the buttons 14 Press the = button. The screen displays the answer 9 450 Press the on button Press the buttons 9 8 1 3 0 + Press the buttons 9 4 5 0 Press the = button. The answer displays the answer 107 580

Rounding off Concept
• If the number that will be rounded off has the digit between 1-4,then number after has to be '0'.
• If the number that will be rounded off has the digit between 5-9 ,then number after has to be '0' and the number that is rounded off is added '1'.

Example of Rounding off Questions

$$107\ 896\div19\ = 5\ 678.7368$$

Round off the answer to :

a) one decimal place

b) two decimal places

Look at the second digit after the decimal point which is 3.

3 is less than 5.

Retain digit 7. Ignore the digits 3, 6 and 8.

5 678.7368 ≈ 5 678.7

Look at the third digit after the decimal point which is 6.

6 is more than 5.

Retain digit 7 and add 1 to digit 3. Ignore the digits 6 and 8.

$$107\ 896\div19\ = 5\ 678.7368$$

Number Pattern Concept

Number pattern is the determination of a series of numbers.

Number Pattern Example

 1.2 Recognise Prime Numbers

 Definition Prime numbers are numbers that are greater than number 1 and only divisible by 1 and itself.

Question

Identify whether the number below is a prime number.

• 17 = Yes
• 21 = No (Can be divisible by 3 and 7)
• 27 = No (Can be divisible by 3 and 9)

 1.3 Seven-Digit Numbers

Exploration of seven-digit numbers

Situasi 1

The pupils' data on 31 August 2014 showed that the total number of primary school pupils was 2,708,211. They consistedn of 1,391,785 boys and 1,316,426  girls.

How to write the place value and digit value of the number 2,708,211

 Digit Place value Digit value 2 Millions 2 000 000 7 Hundred thousands 700 000 0 Ten thousands 0 8 Thousands 8 000 2 Hundreds 200 1 Tens 10 1 Ones 1

1,391,785 if partitioned according to the place value will be as below:

• 1,316,426 rounded off to the nearest hundred thousand becomes 1,300,000.
• 1,300,000 can be written and read as 1.3 million or million.

Round off 1,600,000 to the nearest million.

• 1,600,000 is closer to 2,000,000.
• 1,600,000 when rounded off to the nearest million becomes 2,000,000.
• 1,600,000 is equal to 1.6 million or  million.

Decimal millions and fraction millions

Situation 1

A total of 0/051 million people attended a dinner in conjuction with the Opening of Dataran 1 Malaysia in Pantai Klebang, Melaka organised by the Melaka State Government on 4 February 2010.

 Ones 0 Point . Tenths 0 Hundredths 5 Thousandths 1

 1.4 Relationship of Decimal Millions and Fraction Millions with Whole Numbers

Situation 1

There are about 950 000 species of insects on Earth. Convert 950 000 to decimal millions.

950,000 =  ? million

• 950 000 is less than 1 000 000.
• Therefore, the digit value for millions is 0.
• Then, place a decimal point between the digit for millions and the digit for hundred thousands.
• Ignore all the digit 0 after the digit 5.
• Then, write the word million’.
• = 0.95 million

Situation 2

State 6,500,000 in decimal millions. 6,500,000 = ? million

$$6\ 500\ 000\ = (\dfrac{6\ 5\cancel{00\ 000}}{1\ \cancel{000\ 000}})\ million\\ \quad \quad \quad \quad \quad=(\dfrac{65}{10})\ million\\ \quad \quad \quad \quad \quad=6.5\ million$$

Situation 3

Convert 250 000 to fraction millions.

$$250\ 000\ = (\dfrac{25\cancel{0\ 000}}{1\ 00\cancel{0\ 000}})\ million\\ \quad \quad \quad \quad =\dfrac{25\ \div25}{100\ \div100}\ million\\ \quad \quad \quad \quad =\dfrac{1}{4}\ million$$

 1.5 Solve the problems

Situasi 1

At the end of 2014, several states in Malaysia were hit by severe floods. The table below shows an estimated number of flood victims in three states.

Calculate the total number of flood victims in the three states. Give the answer in decimal millions.

 State Estimated number of victims (people) Kelantan 45 400 Terengganu 10 800 less than Kelantan Pahang 33 000

Solution

$$\begin {array}{rr} \\ \space\space\small{\color{red}1}\space\space\space \small{\color{red}1}\space\space\space\space\space\quad\quad \\ \space 4\space5\,\space\space4\space0\space0\\ \quad\space4\space5\,\space\space4\space0\space0\\ + \quad\space3\space3\,\space\space0\space0\space0 \\\hline\space1\space2\space3\,\space\space8\space0\space0\\\hline \end {array}$$   $$\begin {array}{rr} \\ \space1\space 2\space3\,\space\space8\space0\space0\\ - \quad\space1\space0\,\space\space8\space0\space0 \\\hline\space1\space1\space3\,\space\space0\space0\space0\\\hline \end {array}$$

Situation 2

In 2015, a factory produced 1/5 million kg of cooking oil for export. Production targets in each subsequent year is 2 times the mass of cooking oil compared to the previous year. What is the mass, in kg, of cooking oil produced in 2019?

Solution

 Tahun Jisim (kg) 2015 200 000 2016 2 x 200 000 = 400 000 2017 2 x 400 000 = 800 000 2018 2 x 800 000 = 1 600 000 2019 2 x 1 600 000 = 3 200 000

$$(\dfrac{3\ 2\cancel{00\ 000}}{1\ 00\cancel{0\ 000}})\ juta=\dfrac{32}{10}\ juta\\ \quad \quad \quad \quad \quad \quad \quad \quad = 3.2\ juta$$