ACT Math Practice

Front

What is the formula for calculating the average of a set of numbers?

Back

The average (mean) is calculated by dividing the sum of all numbers by the count of numbers: \( \text{Average} = \frac{\text{Sum of all numbers}}{\text{Count of numbers}} \)

Front

How do you evaluate an expression with variables?

Back

Substitute the variable with its value and then perform the arithmetic operations according to the order of operations (PEMDAS/BODMAS).

Front

What is the least common multiple (LCM) of two numbers?

Back

The least common multiple is the smallest positive integer that is divisible by both numbers.

Front

How do you find the percentage of a mixture?

Back

To find the percentage of a component in a mixture, divide the amount of that component by the total amount of the mixture and multiply by 100.

Front

What is the sine addition formula?

Back

The sine addition formula states that \( \sin(a + b) = \sin(a)\cos(b) + \cos(a)\sin(b) \).

Front

What is the cosine addition formula?

Back

The cosine addition formula states that \( \cos(a + b) = \cos(a)\cos(b) - \sin(a)\sin(b) \).

Front

How do you convert a percentage to a decimal?

Back

To convert a percentage to a decimal, divide the percentage by 100.

Front

What is the relationship between the average of a set of numbers and the addition of a new number?

Back

Adding a new number to a set changes the average. The new average can be calculated by adjusting the total sum and count of numbers.

Front

What is the formula for finding the volume of a cylinder?

Back

The volume of a cylinder is given by \( V = \pi r^2 h \), where \( r \) is the radius and \( h \) is the height.

Front

What is the definition of a variable in mathematics?

Back

A variable is a symbol used to represent an unknown value in mathematical expressions or equations.