Calendar time is a daily activity in the primary years and usually involves tracking daily weather. As kids compare yesterday's weather to the conditions today, it is a good time to consider the likelihood of whether tomorrow will be sunny, rainy or snowy. At math time, the teacher might broach a discussion concerning how likely it is that an event will occur based on a scale of "0" (impossible) to "5 to 9" (varying degrees of "possible") to "10" (certain). On a snowy morning, the question might focus on the likelihood of an outdoor lunch recess.
Another question that students often focus on concerns what hot lunch choices the school will serve on any given day. A formal discussion raises questions such as how likely it is that the lunchroom will serve pizza. Students consider the pattern of lunch choices. The answer may be "definitely" for Friday, which is always pizza day, and "almost never" for Monday. As students work in pairs to analyze the school's monthly menu, they might answer "once a week" if asked about the likelihood of a burrito or hamburger and "never" about the possibility of French onion soup.
Dice games are good for considering questions of fairness. Students wonder whether one player or the other has undue advantage. A typical game might involve a team of four that is given a spinner divided equally into quarters, each a different color. Each player selects a color and takes 10 turns spinning. Results are recorded to show how many times the arrow lands on each color. The teacher tells students to play the game 10 times, and then decide whether it is fair and why. The teams post their data on a graph so the class can make comparisons and discover that the probability of the needle landing on each color is more or less even.
Analysis of fairness is fun when playing dice games, such as one that the National Council of Teachers of Mathematics suggests for pairs of players. Each player is given a six-sided die (an individual number cube) with numbers from 1 to 6. The players both roll their dies and subtract the smaller number from the larger one. If the answer is 0, 1 or 2, player A wins. Player B wins if the sum is 3, 4 or 5. After 12 rounds, the class gathers all the data and consider the game's fairness by discussing their experiences and making a chart listing all possible combinations of rolls and noting their frequency (the game favors answers of 0 to 2).