 ## Explain That

Probability
Probability is a numerical measure of how likely an event is to happen. Probability is measured in fractions between 0 and 1. (0 is impossible; 1 is certain.) Sometimes, probability is represented as a percentage -- from 0 percent to 100 percent.

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Mean, Mode, and Median
Mean, median, and mode are averages. Mean is the average of a group of numbers. Median is the middle number in a list of numbers that have been arranged in order. Mode is the number that occurs most frequently in a list of numbers arranged in order.

Ratio and Proportion
A ratio is a comparison of two numbers. A proportion is a statement (or equation) that says two ratios are equal. If one number in a proportion is not known, cross-multiplying can be used to find the unknown number.

Explain Decimals
Decimals, like fractions, are a way of writing numbers that are larger or smaller than whole numbers. Decimals are represented by a symbol called a decimal point.