Probability - First Grade
What is Probability?
Concept: Probability is the chance that something will happen. It tells us how likely or unlikely an event is!
Why Learn About Probability?
✓ To predict what might happen
✓ To understand chance and luck
✓ To make better decisions
✓ To talk about how likely things are
Probability Words We Use:
• Certain - Will definitely happen
• Likely - Has a good chance of happening
• Unlikely - Probably won't happen
• Impossible - Cannot happen at all
💡 Tip: Probability helps us understand the chance of things happening in our daily life!
1. More, Less and Equally Likely
Concept: We compare events to see which one has a better chance of happening. Some events are MORE likely, some are LESS likely, and some are EQUALLY likely!
📈 MORE LIKELY
Has a BIGGER chance of happening
Example: Picking a red ball when there are 7 red balls and 2 blue balls
📉 LESS LIKELY
Has a SMALLER chance of happening
Example: Picking a blue ball when there are 7 red balls and 2 blue balls
⚖️ EQUALLY LIKELY
Both have the SAME chance of happening
Example: Flipping a coin - getting heads or tails
📝 Example 1: Bag of Marbles
You have a bag with:
5 Red Marbles and 2 Blue Marbles
Question: Which color are you MORE likely to pick?
Answer: RED - because there are MORE red marbles!
You are LESS likely to pick blue because there are fewer blue marbles.
📝 Example 2: Coin Flip
Flipping a coin:
HEADS
TAILS
Question: Are you more likely to get heads or tails?
Answer: EQUALLY LIKELY - Both have the same chance!
A coin has only 2 sides, so heads and tails are equally likely.
How to Compare Likelihood:
✓ Count how many of each item there are
✓ MORE of something = MORE likely to pick it
✓ FEWER of something = LESS likely to pick it
✓ SAME number = EQUALLY likely
💡 Tip: The more you have of something, the more likely you are to pick it!
2. Certain, Probable, Unlikely and Impossible
Concept: We use special words to describe how likely something is to happen - from things that WILL happen to things that CANNOT happen!
The Probability Scale
100% WILL HAPPEN
CERTAIN ✓
GOOD CHANCE
LIKELY/PROBABLE
SMALL CHANCE
UNLIKELY
0% CANNOT HAPPEN
IMPOSSIBLE ✗
✓ CERTAIN
Meaning: Will DEFINITELY happen. 100% sure!
Examples:
• The sun will rise tomorrow
• You will get older
• Night will come after day
👍 LIKELY / PROBABLE
Meaning: Will PROBABLY happen. Good chance!
Examples:
• It will rain during monsoon
• You will eat dinner today
• You will see a bird today
👎 UNLIKELY
Meaning: Probably WON'T happen. Small chance.
Examples:
• It will snow in summer
• You will see a lion on the street
• You will win a lottery
✗ IMPOSSIBLE
Meaning: CANNOT happen. 0% chance!
Examples:
• Flying without wings or a plane
• Living without breathing
• Finding a square circle
📝 Practice Examples
Example 1: Rolling a dice and getting a number from 1 to 6
Answer: CERTAIN - A dice always shows 1-6!
Example 2: Pulling out a green ball from a box with only red balls
Only red balls in the box
Answer: IMPOSSIBLE - There are NO green balls!
Example 3: Picking an apple from a basket with 8 apples and 2 oranges
Answer: LIKELY - More apples than oranges!
💡 Tip: Think about what CAN happen and what CANNOT happen to decide the probability!
Probability Words Quick Reference
| Probability Word | Meaning | Chance | Simple Example |
|---|---|---|---|
| Certain | Will definitely happen | 100% | Sun rising tomorrow |
| Likely/Probable | Probably will happen | High | Eating dinner today |
| Unlikely | Probably won't happen | Low | Snow in summer |
| Impossible | Cannot happen | 0% | Flying without help |
Important Probability Vocabulary
- Probability: The chance that something will happen
- Certain: Will definitely happen (100% sure)
- Likely/Probable: Has a good chance of happening
- Unlikely: Has a small chance of happening
- Impossible: Cannot happen at all (0% chance)
- More Likely: Has a bigger chance than something else
- Less Likely: Has a smaller chance than something else
- Equally Likely: Both have the same chance of happening
🎯 Tips for Probability Success 🎯
- ✓ Count how many of each item to compare likelihood
- ✓ Use probability words in everyday conversations
- ✓ Practice with coins, dice, and marbles
- ✓ Think about what CAN and CANNOT happen
- ✓ Make predictions and see if they come true!
- ✓ Remember: More of something = more likely to pick it
⭐ You're a Probability Expert! ⭐
Fantastic work learning about probability! You now know how to describe how likely things are to happen using words like certain, likely, unlikely, and impossible. You can also compare events to see which is more likely or less likely. These skills help you make predictions and understand chance in everyday life. Keep practicing and you'll become even better at understanding probability!