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Mathematics โ€” Numbers

Subtopic: Whole Numbers (Age 9 โ€” Kenya)

What are whole numbers?

Whole numbers are the numbers: 0, 1, 2, 3, 4, 5, ...
They are used for counting and telling how many. Whole numbers do not include fractions, decimals or negative numbers.

Examples: 0, 7, 25, 314, 1000

Everyday examples (Kenyan context):
  • Number of pupils in a class: 32
  • Number of matatus on a route (counted): 5
  • Kenya has 47 counties โ€” that is a whole number
  • Shillings in a coin example: KSh 20 (whole number of shillings)
Place value (reading whole numbers):

Each digit has a place. From right to left: units, tens, hundreds, thousands...

Number: 4 5 3 2
4
Thousands (4,000)
5
Hundreds (500)
3
Tens (30)
2
Units (2)
Number line (see whole numbers on a line):
0 1 2 3 4 5 6 7 8 9 10
All the dots 0, 1, 2, 3, ... are whole numbers.
How whole numbers behave:
  • Addition: whole + whole = whole (e.g. 4 + 3 = 7)
  • Multiplication: whole ร— whole = whole (e.g. 5 ร— 6 = 30)
  • Subtraction: whole โˆ’ whole may be whole if result โ‰ฅ 0 (e.g. 8 โˆ’ 3 = 5), but 3 โˆ’ 8 is not a whole number (it is negative)
  • Division: sometimes gives whole number (6 รท 3 = 2), sometimes not (5 รท 2 = 2.5)
Try these exercises
  1. Write five whole numbers between 10 and 20.
  2. Which of these are whole numbers? 7, 0, 1.5, โˆ’2, 12
  3. Place these whole numbers in order from smallest to largest: 34, 9, 50, 12.
  4. Fill the blank with a whole number: 15 + ___ = 20
  5. A shop has 18 mangoes. If the seller packs them in groups of 6, how many full groups are there?
  6. Kenya has 47 counties. Is 47 a whole number? (Yes or No)
Answers
  1. Examples: 11, 12, 13, 14, 15 (any five between 10 and 20)
  2. Whole numbers: 7, 0, 12. Not whole: 1.5 (decimal), โˆ’2 (negative)
  3. Order: 9, 12, 34, 50
  4. 15 + 5 = 20, so blank = 5
  5. 18 รท 6 = 3 full groups
  6. Yes โ€” 47 is a whole number
Quick tips:
  • Remember: whole numbers include zero.
  • Decimals like 2.0 are not usually written as whole numbers in class โ€” we write 2 instead.
  • If you see a negative sign (โˆ’), it is not a whole number.
Teacher note: Use objects (stones, beans, coins) to show whole numbers when teaching. For local context, count things from the classroom or around the compound.
๐Ÿ“ Practice Quiz

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