Pre-algebra ACT Practice

Front

What is the formula for calculating the average (arithmetic mean) of two numbers?

Back

The average of two numbers a and b is calculated as: \( \text{Average} = \frac{a + b}{2} \)

Front

If the average of two numbers is 4x and one number is y, how do you find the other number?

Back

The other number can be found using the formula: \( \text{Other number} = 2(4x) - y = 8x - y \)

Front

What is a percentage?

Back

A percentage is a fraction expressed as a part of 100. It is often used to compare relative sizes.

Front

How do you calculate the original price after a discount?

Back

To find the original price (P) after a discount, use the formula: \( P = \frac{\text{Final Price}}{1 - \text{Discount Rate}} \)

Front

What is the median of a set of numbers?

Back

The median is the middle value in a list of numbers sorted in ascending order. If there is an even number of observations, the median is the average of the two middle numbers.

Front

How do you calculate the percentage of a part compared to a whole?

Back

To calculate the percentage, use the formula: \( \text{Percentage} = \left( \frac{\text{Part}}{\text{Whole}} \right) \times 100 \)

Front

What is the slope-intercept form of a linear equation?

Back

The slope-intercept form is given by: \( y = mx + b \) where m is the slope and b is the y-intercept.

Front

How do you find the slope of a line given two points?

Back

The slope (m) can be calculated using the formula: \( m = \frac{y_2 - y_1}{x_2 - x_1} \) where (x1, y1) and (x2, y2) are the coordinates of the two points.

Front

What is the relationship between the average and median in a set of consecutive odd integers?

Back

In a set of consecutive odd integers, the average and median are equal.

Front

How do you convert a percentage to a decimal?

Back

To convert a percentage to a decimal, divide by 100. For example, 25% becomes 0.25.