Mathcounts practice

Front

What is a prime number?

Back

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Front

List all prime numbers between 30 and 40.

Back

The prime numbers between 30 and 40 are 31 and 37.

Front

What is the formula for the mean of a set of numbers?

Back

The mean is calculated by dividing the sum of all numbers by the count of numbers.

Front

If b = 2a, what is the relationship between a, b, and c in the mean of squares problem?

Back

The mean of the squares of a, b, and c is three times the square of their mean.

Front

What is the probability formula for drawing marbles from a bag?

Back

Probability = (Number of favorable outcomes) / (Total number of outcomes).

Front

How do you calculate the probability of drawing two marbles of each color from a bag?

Back

Use combinations to find the number of ways to draw the marbles and divide by the total combinations of drawing six marbles.

Front

What is the maximum integer n such that n^2 < 150?

Back

The maximum integer n is 12, since 12^2 = 144 and 13^2 = 169.

Front

What is the sum of all integers n such that n^2 < 150?

Back

The sum of all possible values of n is 0, considering both positive and negative integers.

Front

How do you find the average of a range of integers?

Back

The average can be found by adding the first and last number, dividing by 2, and multiplying by the number of integers.

Front

What is the average of the integers from 13 to 31?

Back

The average is 22.