Whole Numbers Counting & Writing JSS1 Mathematics Lesson Note

(Counting in Millions, Billions and Trillions)

In mathematics, we use ten basic symbols called digits to write all numbers. These digits are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

When we combine these digits in different ways, we can create any number, no matter how large!

Let’s understand how numbers are grouped:

• Units (Ones): Single digits from 0 to 9
• Tens: Numbers from 10 to 99 (like 10, 25, 67, 99)
• Hundreds: Numbers from 100 to 999 (like 100, 456, 999)
• Thousands: Numbers from 1,000 upwards

The Place Value System

Every digit in a number has a specific position, and this position determines its value. This is called the place value system.

Table of Large Numbers

Quick Memory Tip:

• Million has 6 zeros
• Billion has 9 zeros (3 more than a million)
• Trillion has 12 zeros (3 more than billion)

PLACE VALUE CHART

When reading or writing large numbers, we use a place value chart. Each position has a specific name:

Example: Let’s look at the number 75,800,074,890

This number is read as: Seventy-five billion, eight hundred million, seventy-four thousand, eight hundred and ninety

IMPORTANT RULES FOR WRITING LARGE NUMBERS

1. Group numbers in threes from right to left using commas or spaces
   • Example: 1234567890 becomes 1,234,567,890 or 1 234 567 890
2. Use ‘and’ only before the last two digits (tens and units)
   • Correct: Five hundred and twenty-three
   • Incorrect: Five hundred and twenty and three
3. Zeros act as placeholders – they show that a position has no value
   • Example: 105 means 1 hundred, 0 tens, and 5 units

WORKED EXAMPLES

Example 1: Writing Numbers in Figures

Question: Write in figures: Twenty-five trillion, three hundred and five billion, six hundred and sixty-nine million, one hundred thousand and forty-one.

Solution:

Let’s break this down step by step:

Now we add them together by stacking:

25,000,000,000,000
   305,000,000,000
       669,000,000
           100,000
                41
_____________________
25,305,669,100,041

Answer: 25,305,669,100,041

Example 2: Writing Numbers in Figures

Question: Write in figures: Ninety billion, three hundred and nine million, ninety-one thousand, seven hundred and sixty-three.

Solution:

Breaking it down:

Stacking them:

90,000,000,000
   309,000,000
        91,000
           763
_________________
90,309,091,763

Answer: 90,309,091,763

Example 3: Writing Numbers in Words

Question: Write in words: 456,789,012,345

Solution:

First, let’s identify each group:

• 456 = Four hundred and fifty-six (Billions)
• 789 = Seven hundred and eighty-nine (Millions)
• 012 = Twelve (Thousands)
• 345 = Three hundred and forty-five (Units)

Answer: Four hundred and fifty-six billion, seven hundred and eighty-nine million, twelve thousand, three hundred and forty-five

ORDERING NUMBERS (ASCENDING AND DESCENDING ORDER)

Ascending Order = Arranging from smallest to largest

Descending Order = Arranging from largest to smallest

Example 4: Arranging Numbers in Order

Question: Arrange these numbers in ascending order (smallest to largest):

28,980,579 | 18,967,547 | 2,897,871 | 36,497,871 | 36,479,568 | 18,898,069 | 36,478,967

Solution:

Step 1: Group the numbers properly in threes for easier comparison

Step 2: Compare the leftmost digits first (the millions place)

• Numbers starting with 2: 2,897,871
• Numbers starting with 18: 18,898,069 and 18,967,547
• Numbers starting with 28: 28,980,579
• Numbers starting with 36: 36,478,967, 36,479,568, and 36,497,871

Step 3: Within each group, compare the next digits to the right

Answer (Ascending Order):

2,897,871 | 18,898,069 | 18,967,547 | 28,980,579 | 36,478,967 | 36,479,568 | 36,497,871

PRACTICE EXERCISES

Exercise 1: Writing Numbers in Words

Write the following numbers in words:

(a) 567,256,789

(b) 18,000,901,234

(c) 3,456,789,012

(d) 125,000,000,000

Exercise 2: Writing Numbers in Figures

Write the following in figures:

(a) Three hundred and twenty-nine billion, five hundred and sixty-two million, eight hundred and one thousand, four hundred and thirty-three

(b) Fifteen trillion, six hundred and seventy-one billion, three hundred and ninety-one million, eighty-eight thousand, five hundred and fifty-five

(c) Seven hundred and eight million, forty-five thousand, two hundred and one

(d) Ninety-nine trillion, nine hundred and ninety-nine billion, nine hundred and ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine

Exercise 3: Arranging Numbers

Arrange the following numbers in:

(i) Ascending order (smallest to largest)

(ii) Descending order (largest to smallest)

1,009,085,941 | 1,288,890,563 | 102,458,001 | 999,999,999 | 10,009,002 | 105,879,894,167

Exercise 4: Fill in the Blanks

(a) One million has _____ zeros

(b) 5,000,000 is read as _____

(c) The place value of 7 in 37,456,891 is _____

(d) The largest 3-digit number is _____

(e) One billion is _____ times larger than one million