🔢 Understanding 'Before' and 'After' Numbers in Grade 1
In Grade 1, understanding the numbers that come 'before' and 'after' a given number is a foundational skill. It helps build number sense and prepares students for more advanced math concepts. Let's break it down:
⏮️ Definition of 'Before'
The number that comes 'before' a given number is the number that is one less than the given number. It's like counting backwards by one.
⏭️ Definition of 'After'
The number that comes 'after' a given number is the number that is one more than the given number. It's like counting forwards by one.
📊 Comparison Table: 'Before' vs. 'After'
| Feature |
'Before' |
'After' |
| Definition |
One less than the given number |
One more than the given number |
| Operation |
Subtraction ( $-1$ ) |
Addition ( $+1$ ) |
| Number Line Direction |
Moving to the left on a number line |
Moving to the right on a number line |
| Example (For the number 5) |
4 |
6 |
🔑 Key Takeaways
- ➖ Subtracting 1: To find the number 'before', we subtract 1 from the given number. For example, the number before 7 is $7 - 1 = 6$.
- ➕ Adding 1: To find the number 'after', we add 1 to the given number. For example, the number after 7 is $7 + 1 = 8$.
- ↔️ Number Line: Imagine a number line. 'Before' is to the left, and 'after' is to the right.
- 💡 Real-World Examples: Think about lining up for a game. The person 'before' you is ahead, and the person 'after' you is behind!