FTCE General Knowledge Math Practice Test

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Prepare for the FTCE General Knowledge Math Test with interactive quizzes and detailed explanations. This resource will enhance your math skills and boost your confidence before the exam. Conquer the test and excel in your teaching career!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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What is the formula for calculating combinations?

n!/(n+r)!
n!/(r!(n-r)!)
(n-r)!/n!
n^r/r!

The correct answer is: n!/(r!(n-r)!)

The correct formula for calculating combinations is indeed n!/(r!(n-r)!). This formula is used to find how many ways you can choose r items from a set of n items without regard to the order of selection. In the formula, n! represents the factorial of n, which is the product of all positive integers up to n. The term r! accounts for the arrangements of the selected items, as the order of the chosen items does not matter in combinations. Meanwhile, (n-r)! represents the factorial of the remaining items that are not chosen. This combination formula is essential in various mathematical and statistical applications, especially in probability and counting problems, as it allows you to determine the number of possible subsets that can be formed from a larger set. The other options provided do not correctly yield the combination count; they either represent permutations or erroneous constructions of factorials that don’t accurately address the concept of combinations.