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How Do You Know If a Number is Even?
Grade Level:
Class 1
Maths, Computing, Algorithms
Definition
What is it?
You know if a number is even by checking its last digit. If the last digit is 0, 2, 4, 6, or 8, then the entire number is even. Even numbers are always divisible by 2 without leaving any remainder.
Simple Example
Quick Example
Imagine you have 10 ladoos to share equally between two friends. Can you do it without breaking any ladoos? Yes, each friend gets 5 ladoos. Since 10 can be divided equally by 2, 10 is an even number. Its last digit is 0.
Worked Example
Step-by-Step
Let's check if the number 246 is even.
Step 1: Look at the last digit of the number 246.
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Step 2: The last digit of 246 is 6.
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Step 3: Recall the list of even digits: 0, 2, 4, 6, 8.
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Step 4: Since 6 is in the list of even digits, 246 is an even number.
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Answer: Yes, 246 is an even number.
Why It Matters
Understanding even numbers is a basic building block for many areas in Maths and Computing. It helps in understanding patterns, data sorting, and even in coding algorithms. Careers like software development, data analysis, and financial modeling use these foundational concepts every day.
Common Mistakes
MISTAKE: Only checking the first digit of a number. For example, thinking 34 is odd because 3 is odd. | CORRECTION: Always check the LAST digit of the number (the digit in the ones place) to determine if it's even or odd.
MISTAKE: Confusing even numbers with numbers divisible by 5. For example, thinking 25 is even because it ends in 5. | CORRECTION: Even numbers must end in 0, 2, 4, 6, or 8. Numbers ending in 5 are odd.
MISTAKE: Believing that large numbers are always even or always odd. For example, thinking 1234567 is too big to be odd. | CORRECTION: The size of the number doesn't matter; only its last digit determines if it's even or odd.
Practice Questions
Try It Yourself
QUESTION: Is the number 78 an even number? | ANSWER: Yes, because its last digit is 8.
QUESTION: Which of these numbers is NOT even: 10, 23, 44, 56? | ANSWER: 23, because its last digit is 3, which is not 0, 2, 4, 6, or 8.
QUESTION: A shopkeeper has 145 pens. Can he pack them into boxes, with 2 pens in each box, without any pens left over? | ANSWER: No, because 145 is an odd number (its last digit is 5), so it cannot be divided equally by 2.
MCQ
Quick Quiz
Which of these numbers is an even number?
15
27
32
49
The Correct Answer Is:
C
The correct answer is 32 because its last digit is 2, which is an even digit. Options A, B, and D end in 5, 7, and 9 respectively, making them odd numbers.
Real World Connection
In the Real World
In daily life, when you buy items like samosas or pens, they often come in pairs or groups. If you buy 12 pens, you know you can divide them into 2 equal groups of 6. This is because 12 is an even number. Even in computer programming, checking if a number is even or odd is a fundamental step in many tasks, like sorting data or creating patterns.
Key Vocabulary
Key Terms
EVEN NUMBER: A number that can be divided by 2 without any remainder, ending in 0, 2, 4, 6, or 8. | ODD NUMBER: A number that leaves a remainder of 1 when divided by 2, ending in 1, 3, 5, 7, or 9. | LAST DIGIT: The digit in the ones place of a number. | DIVISIBLE: Capable of being divided by another number without a remainder.
What's Next
What to Learn Next
Great job understanding even numbers! Next, you should learn about 'How Do You Know If a Number is Odd?'. This will help you understand the opposite type of number and complete your basic knowledge of number properties.
