Classifying Numbers by Their Properties
Primary 4 · Mathematics
Classifying Numbers by Their Properties
Lesson 1 of 5
20 min
Let's begin
At break time, the P4 class lines up in pairs to go back to class. On Monday there are 28 pupils and everybody has a partner. On Tuesday one pupil is at home sick, and one child is left without a partner. What is special about 28, and about 27?
The natural numbers are the numbers we use for counting: 0, 1, 2, 3, 4, 5 … They never end, because you can always add 1 more. (In this course we start the natural numbers at 0. Some books start them at 1.)
Put a number of beans into pairs.
So 28 is even (everyone had a partner) and 27 is odd (one pupil was left over).
You do not need beans for big numbers. Just look at the ones digit:
Tip
Only the last digit matters. 98 765 is odd because it ends in 5. The other digits do not change the answer.
Work each one in your exercise book first. Then tap Show answer to check.
Is 45 even or odd?
Answer: Odd, because it ends in 5.
Is 3 758 even or odd?
Answer: Even, because it ends in 8.
Write the even numbers between 21 and 31.
Answer: 22, 24, 26, 28, 30
Without adding, is 37 + 49 even or odd?
Answer: Even. Odd + odd = even. (The sum is 86.)
What is the smallest odd natural number?
Answer: 1
What you learned today
Sources and credits
Written by Ganzaa. The story, diagram and practice questions are original.
Quick check
Which number is odd?
