Whole Numbers Counting & Writing – JSS1 Mathematics Lesson Note (First Term)

Whole numbers are written with the ten digits 0 to 9. The position of each digit gives its place value, so digits can be combined to write any number, however large. Large numbers are grouped in threes from the right and named in thousands, millions, billions and trillions.

Behavioural objectives

By the end of the lesson, students should be able to:

• name the digits and the groups of whole numbers (units, tens, hundreds, thousands);
• state the number of zeros in a million, a billion and a trillion;
• give the place value of a digit using the place value chart;
• write large numbers in figures and in words;
• arrange whole numbers in ascending and descending order.

What are digits and how are numbers grouped?

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.

Numbers are grouped as follows:

• 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

What is 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 a billion)

What is the place value chart?

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

Example: Take the number 75,800,074,890.

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

What are the 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: Break the number into parts, then add the parts.

Adding the parts:

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:

Adding the parts:

Answer: 90,309,091,763

Example 3: Writing numbers in words

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

Solution: First, 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

How do we arrange numbers in ascending and descending order?

Ascending order means arranging from smallest to largest.

Descending order means 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: Count the digits. A number with fewer digits is smaller, so 2,897,871 (7 digits) is the smallest. The other numbers have 8 digits, so compare their leftmost digits first (the ten-millions place, then the millions place):

• Numbers starting with 2: 2,897,871 (7 digits, so it is only 2 million)
• 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

Evaluation

1. How many zeros are in one billion and in one trillion?
2. Write 5,000,000 in words.
3. Write in figures: Forty-two million, five hundred and six thousand, three hundred and eight.
4. What is the place value of 8 in 18,967,547?

Assignment

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