Mathematics
Grade 1
15 min
Certain, probable, unlikely, and impossible
Certain, probable, unlikely, and impossible
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1
Introduction & Learning Objectives
Learning Objectives
Identify an event as certain.
Identify an event as impossible.
Describe an event as probable or likely.
Describe an event as unlikely.
Sort pictures of events into the four categories.
Explain why an event is probable or unlikely by counting.
If you have a bag of only red crayons 🖍️, is it possible to pull out a blue one? Let's find out!
Today, we will learn special words to talk about chances. These words help us guess what might happen. It is fun to think about the future!
Real-World Applications
Guessing if it will rain today 🌦️
Knowing you will eat lunch at school 🥪
Playing a board game with a spinner 🎲
Wondering if you will see a squirrel on the way home 🐿️
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Key Concepts & Vocabulary
TermDefinitionExample
CertainSomething that will ALWAYS happen. It is a sure thing! 👍It is certain that the sun will rise in the morning. ☀️
ProbableSomething that will MOST LIKELY happen. It has a very good chance. 😊If a jar has 9 red balls and 1 blue ball, it is probable you will pick a red one.
UnlikelySomething that will probably NOT happen. It has a small chance. 🤔It is unlikely that your dog will learn to talk tomorrow. 🐶
ImpossibleSomething that can NEVER happen. No way! 🚫It is impossible for a pig to fly. 🐷
ChanceHow likely it is that something will happen. It's like a guess we can measure.The chance of flipping a coin and getting heads is probable. 🪙
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Core Formulas
The Chance Line
Impossible <--- Unlikely <--- Probable ---> Certain
We can place events on a line. Things that can't happen are on the left. Things that must happen are on the right.
The Counting Rule
More items = More probable. Fewer items = More unlikely.
When picking from a group, you are more likely to pick the item there is most of. Count to find out!
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Challenging
Spinner A has 2 equal parts: red and blue. Spinner B has 4 equal parts: red, blue, green, and yellow. On which spinner is it MORE probable to land on red?
A.Spinner A
B.Spinner B
C.It is impossible on both
D.It is the same for both
Challenging
A bag has 3 red blocks and 4 blue blocks. If you add one more BLUE block, what happens to the chance of picking a RED block?
A.It becomes more likely
B.It becomes less likely
C.It does not change
D.It becomes impossible
Challenging
A drawer has 5 red socks and 5 blue socks. You pick one red sock and put it on. What is the chance you will pick a RED sock next?
A.It is now probable you will pick a red sock
B.It is now unlikely you will pick a red sock
C.It is now certain you will pick a red sock
D.It is now impossible to pick a red sock
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