Awesome Adventures in Numbers!
Hello, Super Mathematician! Get ready to explore the exciting world of numbers. In these notes, we're going to learn about two cool things: Odd & Even numbers, and how to do Counting Onwards & Backwards. It's like being a number detective and a time traveller all at once! Knowing this helps us understand how numbers work and makes counting games much more fun. Let's begin!
Counting Onwards & Backwards: The Number Rocket!
Imagine you have a big number line in front of you, like a long road with numbers on it. Counting is just like walking along this road!
Counting Onwards (Forwards) - Blast Off!
Counting onwards, or forwards, is just like counting up. You are moving to bigger numbers. Think of it like a rocket launching into the sky: 5, 4, 3, 2, 1... BLAST OFF! 1, 2, 3, 4, 5... going higher and higher!
How to do it:
1. Find your starting number.
2. Hop to the next number that is one BIGGER.
3. Keep hopping until you have taken enough steps!
Example: Let's start at the number 8 and count onwards by 3 steps.
- We start at 8.
- First hop: 9 (one more than 8)
- Second hop: 10 (one more than 9)
- Third hop: 11 (one more than 10)
Hooray! We landed on 11.
Counting Backwards - Coming in for a Landing!
Counting backwards is the opposite. You are moving to smaller numbers. It's like a rocket coming back to Earth: 10, 9, 8, 7... getting closer and closer to the ground.
How to do it:
1. Find your starting number.
2. Step back to the number that is one SMALLER.
3. Keep stepping back until you have taken enough steps!
Example: Let's start at 15 and count backwards by 4 steps.
- We start at 15.
- First step back: 14 (one less than 15)
- Second step back: 13 (one less than 14)
- Third step back: 12 (one less than 13)
- Fourth step back: 11 (one less than 12)
Great job! We landed on 11.
Quick Review: Counting Power!
- Onwards (Forwards) = Numbers get BIGGER.
- Backwards = Numbers get SMALLER.
Key Takeaway: Counting onwards is like climbing up a ladder, and counting backwards is like sliding down a slide! It's all about which direction you're going with the numbers.
Odd & Even Numbers: The Buddy System!
Have you ever noticed that when you line up your toys, sometimes you can give every toy a partner, and sometimes there's one left all by itself? Numbers are just like that!
Meet the Even Numbers (The Perfect Pairs!)
An even number is any number where everything can be put into pairs, with nothing left over. They are tidy and balanced! Think about things that always come in pairs:
- A pair of shoes (2 shoes)
- A pair of gloves (2 gloves)
- Your eyes (2 eyes)
Example: Let's look at the number 8. If we have 8 cookies, can we share them equally between 2 friends? Yes! Each friend gets 4 cookies. So, 8 is an EVEN number.
Memory Trick: All even numbers end with one of these digits: 0, 2, 4, 6, 8.
Examples: The numbers 12, 26, 40, and 98 are all EVEN because of their last digit!
Meet the Odd Numbers (The One Left Out!)
An odd number is a number that, when you try to make pairs, always has one left over. It's the "odd one out"!
Example: Let's look at the number 5. If we have 5 pencils and try to make pairs, we get two pairs and... one pencil is left all alone! So, 5 is an ODD number.
Memory Trick: All odd numbers end with one of these digits: 1, 3, 5, 7, 9.
Examples: The numbers 11, 23, 57, and 89 are all ODD because of their last digit!
Don't worry if this seems tricky at first. The best way to learn is to look at the last digit. It's a secret code that tells you the answer every time!
Watch Out! A Common Mistake!
What about the number zero (0)? It can be confusing! But here's the rule: Zero (0) is an EVEN number. Why? Because you can share zero things between two people perfectly – they both get zero, and there's nothing left over!
Did you know?
In many places, houses on one side of a street have even numbers (like 2, 4, 6 Main Street) and houses on the other side have odd numbers (like 1, 3, 5 Main Street). This helps the mail carrier find your house more easily! Next time you are outside, check the numbers on the mailboxes.
Key Takeaway: To know if a number is odd or even (even big numbers up to 100!), just look at the very last digit. If it's 0, 2, 4, 6, or 8, it's EVEN. If it's 1, 3, 5, 7, or 9, it's ODD. It's a simple trick that always works!