Basic Probability: Likely and Unlikely
Compare chances using everyday events and simple models
Basic Probability: Likely and Unlikely
Compare chances using everyday events and simple models
Math - Grade 4-5
- 1
A bag has 8 red marbles and 2 blue marbles. If you pick one marble without looking, is it more likely to be red or blue? Explain.
Compare the number of red marbles with the number of blue marbles.
It is more likely to be red because there are 8 red marbles and only 2 blue marbles in the bag. - 2
Choose the best probability word for this event: The sun will rise tomorrow. Use one of these words: certain, likely, equally likely, unlikely, impossible.
The event is certain because the sun rising tomorrow is expected to happen. - 3
A spinner has 4 equal sections: green, green, green, and yellow. Is landing on yellow likely or unlikely? Explain.
Count how many sections are yellow compared with the total number of sections.
Landing on yellow is unlikely because only 1 of the 4 equal sections is yellow. - 4
A number cube has the numbers 1 through 6. Is rolling a number less than 7 certain, likely, unlikely, or impossible? Explain.
Rolling a number less than 7 is certain because every number on the cube is less than 7. - 5
A jar has 5 orange candies and 5 purple candies. If you choose one candy without looking, are you more likely to choose orange, more likely to choose purple, or equally likely to choose either? Explain.
Equal amounts mean equal chances.
You are equally likely to choose orange or purple because the jar has the same number of each color. - 6
Describe one event at school that is likely to happen on a normal school day.
An example of a likely event is that students will read, write, or solve math problems during class because those activities happen on most school days. - 7
A basket has 1 apple, 1 banana, 1 orange, and 1 pear. If you choose one fruit without looking, is choosing an apple likely, unlikely, certain, or impossible? Explain.
Think about how many choices are apples and how many choices are not apples.
Choosing an apple is unlikely because only 1 of the 4 fruits is an apple. - 8
A weather report says there is a 90% chance of rain today. Is rain likely or unlikely? Explain.
Rain is likely because a 90% chance is close to 100%, which means the event has a high chance of happening. - 9
A spinner has 8 equal sections. Six sections are blue and two sections are red. Which color is the spinner more likely to land on? Explain.
The color with more equal sections has the greater chance.
The spinner is more likely to land on blue because 6 sections are blue and only 2 sections are red. - 10
A bag contains only green cubes. If you pull out one cube without looking, what is the chance of pulling out a red cube: certain, likely, equally likely, unlikely, or impossible? Explain.
Pulling out a red cube is impossible because there are no red cubes in the bag. - 11
A class has 18 students who brought lunch from home and 6 students who are buying lunch. If one student is chosen at random, is that student more likely to have brought lunch or to be buying lunch? Explain.
Compare 18 and 6.
The student is more likely to have brought lunch because 18 students brought lunch and 6 students are buying lunch. - 12
A box has 3 star stickers and 9 heart stickers. If you choose one sticker without looking, is choosing a star sticker likely or unlikely? Explain.
Choosing a star sticker is unlikely because there are fewer star stickers than heart stickers. - 13
Write an example of an impossible event involving a regular number cube labeled 1 through 6.
Choose something that cannot happen with the numbers shown on the cube.
An example of an impossible event is rolling an 8 because a regular number cube only has the numbers 1 through 6. - 14
A bowl has 4 chocolate cookies and 4 oatmeal cookies. If you choose one cookie without looking, describe the chance of choosing a chocolate cookie.
Choosing a chocolate cookie is equally likely as choosing an oatmeal cookie because there are 4 of each kind. - 15
Order these events from least likely to most likely: rolling a 6 on a number cube, rolling a number from 1 to 6 on a number cube, rolling a 10 on a number cube.
A regular number cube has only the numbers 1, 2, 3, 4, 5, and 6.
The order from least likely to most likely is rolling a 10, rolling a 6, and rolling a number from 1 to 6. Rolling a 10 is impossible, rolling a 6 is possible but not likely, and rolling a number from 1 to 6 is certain.