Pupils have been investigating ideas of chance and uncertainty, and exploring ways in which we can use numbers to show how likely something is to happen.
We can show the chance of something happening by:
- Using words like “certain”, “very likely”, “unlikely” or “impossible”;
- Using a number from 0 to 1 (0 = impossible and 1 = certain)
- Using phrases like “1 out of 2”, “3 out of 100” or “2 out of 5”;
- Using a fraction or a percentage. (For example, “1/3 likely” or “a 55% chance”.)
If we know how likely different things are to happen, we can show whether one outcome is more or less likely than another.
For example, if I roll a dice, the chance of rolling a six is “1 out of 6”. The chance of rolling an odd number is “3 out of 6”. So I am more likely to roll an odd number than a six.
Sometimes, two outcomes have an equal chance of happening. If I toss a coin, the chance of getting ‘heads’ is “1 out of 2”, and the chance of getting ‘tails’ is also “1 out of 2”. So both heads and tails are equally likely to happen.
Examples of our investigations
Here are a couple of questions for you to think about yourself. If you’re not sure, ask a P5 to explain the answers – they may surprise you!
(1) I have two red socks and one green sock in a drawer. Without looking, I take two socks out of the drawer. Am I more likely to (a) have a pair; or (b) not have a pair?
(2) I have just tossed a coin four times in a row, and it has come out heads every time. How likely is it that it will be heads next time as well?
(3) In a bag, I place two red cubes, two blue cubes, and a yellow cube. Without looking, I take two cubes out of the bag. Is it more likely that: (a) I will choose two cubes that are the same colour; or (b) I will choose two cubes that are different colours?