Hot Math How-Tos

How To: Work with surveys and samples in statistics

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to work with surveys and samples in general statistics.

How To: Write an analytical proof of the quadratic formula

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to write a formal analytical proof of the quadratic formula.

How To: Perform a quadratic regression with a calculator

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to find the partial derivative of a vector-valued function using a calculator to perform...

How To: Identify an exponential model

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to identify and work with exponential models.

How To: Solve radical expressions with higher roots

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to find the partial derivative of a vector-valued function with higher-value roots.

How To: Work with linear, quadratic & exponential models

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to work with linear, quadratic and exponential models.

How To: Factor by grouping in intermediate algebra

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this free math lesson, you'll learn how to factor by grouping in intermediate-level algebra.

How To: Get the volume of rectangular prisms

Attention math heads! Brush up on your high school math skills with help from this video made by a Lincoln High School teacher on how to find the volume of a rectangular prism. Find the answer you're looking for with help from this educational math video.

How To: Plot absolute values on a number line

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to plot absolute values on a number line in simple algebra/geometry.

How To: Solve an equation for a variable in Microsoft Excel

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to solve an equation for a variable in algebra.

How To: Solve an absolute value equation

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to work with absolute value equations.

How To: Find partial derivatives of vector-valued functions

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to find the partial derivative of a vector-valued function in linear algebra or vector c...

How To: Find mean, median, & mode (averages)

If you use Microsoft Excel on a regular basis, odds are you work with numbers. Put those numbers to work. Statistical analysis allows you to find patterns, trends and probabilities within your data. In this MS Excel tutorial from everyone's favorite Excel guru, YouTube's ExcelsFun, the 34th installment in his "Excel Statistics" series of free video lessons, you'll learn how to use MEAN, MEDIAN, MODE. These measures give us a typical value, a measure of central tendency one value that can repr...

How To: Find outliers using the Z-score method

If you use Microsoft Excel on a regular basis, odds are you work with numbers. Put those numbers to work. Statistical analysis allows you to find patterns, trends and probabilities within your data. In this MS Excel tutorial from everyone's favorite Excel guru, YouTube's ExcelsFun, the 49th installment in his "Excel Statistics" series of free video lessons, you'll learn how to find outliers with the +/- 3 Z-score rule and the ABS function. See how to do a box plot by hand and in Excel. For th...

How To: Parametrize a surface with two parameters

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to parameterize a surface with two parameters.

How To: Find the position of a vector-valued function

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to determine the position vector-valued function for parameterization.

How To: Turn a mixed number into an improper fraction

Sometimes math problems are easier to solve if you can convert a number into different types. In this tutorial, taught by a real math teacher, learn how to take a mixed number and turn it back into an improper fraction, and vice versa. This process won't take long and it will help you on many types of algebra problems.

How To: Find the volume of a cylinder

Need help calculating the volume of a cylinder? It's easy! So easy, in fact, that a complete and thorough overview of the process can be presented in forty-five seconds' time. Study for your next geometry test or just finish your homework with this free video math lesson, which demonstrates how to find the volume of a cylinder using v=pr^2h.

How To: Calculate the United States unemployment rate

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to calculate the US unemployment rate given the raw data.

How To: Work with radical equations in algebra

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to work with radical algebraic equations.

How To: Solve radical equations with extraneous solutions

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to work with radical equations containing invalid or "extraneous" solutions.

How To: Simplify radical expressions in algebra

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to reduce and simpify rational expressions in algebra.

How To: Visualize data with a histogram chart

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to create a simple histogram chart.

How To: Find the midpoint of a line segment in geometry

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to find the midpoint of a line segment in geometry.

How To: Graph data by hand with a stem-and-leaf plot

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to visualize statistical data with a hand-drawn stem-and-leaf chart.

How To: Geometrically prove the Pythagorean theorem

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to perform a geometric proof of the Pythagorean theorem.

How To: Multiply and divide rational expressions in algebra

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to multiply and divide rational algebraic expressions.

How To: Change percents into fractions

Fractions are numbers written in the form a/b, where a, b are integers. Fractions can also be expressed in the form of percents by multiplying the value of the fraction with hundred. So we can always change percents to fractions and also fractions to percents. Remember that percent means hundredth. So percent means a fraction with a denominator of hundred. When you are given percents and asked to calculate its fraction, divide the percent with hundred. Now this fraction can be further reduced...

How To: Find the perimeter of a shape

Two dimensional objects are measured in terms of perimeter and areas. A perimeter of a two dimensional object is the distance around that object. If you want to find the perimeter of an object, all you need to do is add up each one of the lengths of sides of that object. If you have a small figure like triangle, first compute the length of the three sides. Now adding these three sides gives you the perimeter of the triangle. A larger or more complicated shape might have more number of sides. ...

How To: Use Heron's formula

Area of a triangle can be calculated when you have the length of its base and height. In this case the area is 1/2 times the base and its height. If you do not know the height of the triangle but know the lengths of all the sides of the triangle then you can calculate its area using the Herons formula. First to use it you need to computer the semi perimeter of the triangle S, which is S = (a + b + c)/2, where a, b, c are the lengths of the sides of the triangle. Now the area of the triangle i...

How To: Graph an inequality in slope-intercept form

This how to video shows you how to graph an inequality in slope intercept form. First, graph the line. Depending on the inequality, use a dash or solid line. Use a solid line for less than or equal to or greater than or equal to. Use a dash line for greater than or less than. If y is less than or less than or equal to, shade the bottom area of the line. If it is y is greater than or greater than or equal to, shade the top area of the line. Check your answer by substituting in any point from t...

How To: Do normal probability calculations on a calculator

Probability computation is a complex process and even using a calculator can be difficult. But normal probability calculations can be performed quickly with the help of calculator once you know how to use it. So when you have to calculate a probability from a normal distribution you can use the functions on your scientific calculator. You can use the normal CDF function from you calculator to compute the area under a normal curve. The function requires lower band and upper band values, the me...

How To: Compare the difference of annual percentage rate

This video is about Annual percentage Rate(APR) and the Effective APR rate.The video begins with an example of a credit card which has a APR rate of 22.9% and daily periodic rate of 0.06274%.You can get the APR rate by multiplying the daily peiodic rate with 365, which in this case will be 0.06274*365 which is equal to 22.9.If you convert the daily periodic rate into decimal values , it will be 0.006274.So for example, if you have 1 dollar in your balance on day 1, on day 2 you will owe 1.000...

How To: Find the median & inter-quartile range

This video shows us the method to find the median and the inter-quartile range. The first step involves the arrangement of the numbers in the ascending order. Median is the middle number. The middle number is the number at (number of numbers + 1)/2 if the number of numbers is odd or the (number of number)/2 if the number of numbers is even. In the example the number is located at [(11+1)/2] or the 6th number. The inter-quartile range is higher quartile - lower quartile. The higher quartile is...

How To: Solve equations involving square roots

Equations involving square roots are difficult to solve because of the complexity involved in performing operations on the square root terms. But you can follow a series of steps to solve these problems easily. To solve these kind of problems first isolate the square root term on one side of the equation and the non square root terms on the other side of the equation. Now in the next step square both sides of the equation. This gets rid of the square root on the left hand side and the equatio...