Science Experiments Humanities Teaching Legal Issues Education WonderHowTo

Math Features

iOS 18 Tips, Tricks, How-Tos, News

How To: Remember and recite pi to eight decimal places

Looking for an easy way to impress the math geeks in your life? This brief clip from the BBC will help you memorize pi to eight decimal places without breaking a sweat through use of a simple mnemonic device: "How I wish I could calculate pi easily today." (Hint: Count the number of letters in each word.) Easy as pi(e).

How To: Find the area and volume of prisms

This helpful video gives simple step by step instructions on how to find area and volume of prisms. To find the area of a prism you must first find the area of the base, it may be rectangular, triangular, or otherwise. You must then multiply the area of the base times the height. Examples of all types of scenarios are given to better explain the method of finding the area. To find the volume of a triangular prism you must first find the area of the base. The next step is multiplying the area ...

How To: Fill a cone

This is a very interesting instructional video on how to fill a cone. Pour oil into a cone of diameter 30 inches and depth 40 inches. Now find the volume of the oil as a function of its depth. Volume = 1 over 3 phi rsquare h. We don't know the height and depth of the oil poured into the cube. Draw similar right angled triangles. In one right angled triangle the height is 40 inches and in the other triangle it is h. Similarly the height is 40 inches and h respectively. Now rover h =15 over 40....

How To: Find the area of a trapezoid

Get help with your math homework and learn to find the area of a trapezoid by watching this video. Following along while four examples are solved, the viewer will learn how to calculate the area when all the required measurements are given and will learn to calculate distance of one side when the area of the trapezoid is known. If you are learning about measurement in school or are trying to find the areas of a trapezoid for another reason (maybe you are carpeting an oddly shaped room), this ...

How To: Factor a trinomial by GCF then grouping

In this tutorial the instructor shows how to factor a trinomial with Greatest Common Factor (GCF) and then how to group it. The first thing you have to do when you want to factor a trinomial is look for the GCF. First factor the numerical coefficients of the terms of the equation. Now separate out the common numerical factor and if any common variable. This leaves you with a binomial to be factored. Now to solve this multiply the numerical coefficients of the first term and the last term and ...

How To: Reduce fractions for easier manipulation

You should always try to reduce a fraction until it can't be reduced anymore. To do this, look at your fraction and figure out the greatest number BOTH the numerator and denominator can be divided by. This is called the GCF - the greatest common factor. In the video, the problem you must solve is (15/18). What number can be divided into both 15 and 18 evenly? The answer is 3.

How To: Solve an equations for x

This video demonstrates how to solve algebraic equations of the first degree for the variable, "X"; in other words, the variables contained in these equations are not raised to any power other than one, which is implicit. The video starts out with an example of such an algebraic equation. Before beginning to solve the equation, the video explains the meaning of the equals sign, the definition of an equation, and what a variable is. Next the video explains what is meaning by "solving for X". T...

How To: Understand negative exponents

In this video, we learn how to understand negative exponents. The one rule you have to remember is when you have a number with a negative power, then you need to divide it over one. You can take this term and put it in the denominator of your fraction to make it a positive exponent. For example, if you have 5 to the -1, then you can move the 5 to the denominator and get 1/5, which is the same exact thing! This is one of the most basic rules in math. Once you understand this, simplifying fract...

How To: Find the length of a side of a triangle using cosine

To find the length of a side of a triangle using cosine, you first need to find the angle and which sides are given. After you determine the angle and given sides, you'll need to figure out which trigonometric ratio to use. If you are given the adjacent side and the hypotenuse, you need to use cosine to solve. The degree equals adjacent divided by hypotenuse. In the example, Cos 39=3.5/x. After simplifying the equation, we found x to be 4.49. If the directions ask you to round, be sure to rou...

How To: Find the area of a triangle

In this video, learn how to calculate one of the most important puzzlers in math - the area of a triangle. This is one of the first things you will learn in geometry and is helpful in math as well as science classes. Check out this tutorial if you are having trouble grasping this concept. This video will show you how to calculate the area of a triangle easily and in detail. Master this and you will pass that next test for sure!

How To: Find the area of a circle

In this tutorial, we learn how to find the area of a circle. First, you will need to know the formula for finding the area of a circle, which is Area=Pi(r)squared. Now, find the radius of the circle in question. After this, fill in the radius to the equation and start to do the math. The area will equal what the radius is, times pie and squared. After you do the math for this, you will have found the area of the entire circle. Make sure you label the number with units, or else your answer wil...

How To: List the factors of a number

In this tutorial the author shows how to factor a number. He says that factoring means to find all the smaller numbers which can be multiplied to obtain the original number. He says that the number one and the number it self are the factors of every number. Now to find the factor of a number he starts with 2 and tries to divide that number with 2. If he is able to divide it, it implies that 2 is a factor of that number. He now does this with each and every number between 1 and the number it s...

How To: Add fractions with unlike denominators

In order to add fractions that are not alike, you will need to find the lowest common denominator. This is the least common multiple of the fractions. To add 2/3 plus 1/5, you will need to find the lowest common denominator. Here, it is best to think of all of the multiples of the denominators. If it helps, make a list. For 3, it is 3, 6, 9, 12, 15, etc. For five, the multiples are 5, 15, 20, 25, etc.

How To: Find the formula of a piecewise function given a graph

This video shows how to find the formula of a piecewise function when given a graph. The first step is to write a definition for the graph, which is done by identifying the different domains shown in the graph. The second step is writing formulas for each domain specified by the lines in the graph. The point-slope formula is used to identify the slope and y-intercept for the leftmost domain, which has a sloped line. A point and horizontal line make for simpler equations in the other pieces of...

How To: Find the area of a parallelogram using geometry

The video shows us how to find the area of parallelogram using geometry. Here in this video it is done by using an example where the parallelogram is given ABCD. The area of the parallelogram is base times height (bh). Here the base is given as 15 but the height is not known but it is represented by the segment BD. To find the value of h, let’s use right triangle BDC on the right side of the figure. Since base is 15 and the opposite side of the parallelogram is congruent, the hypotenuse of th...

How To: Find the area of irregular shapes

This video explains how to find the area of irregular shapes. Draw the shape on a grid or graph paper. This will help you divide your shape into pieces. Draw dotted lines to divide the shape into squares, rectangles or triangles. For instance, if you have an "L" shape, you can divide the shape into two rectangles. Be sure your shapes do not overlap. Calculate the area of each individual shape. The graph paper will help you determine the length and width of each shape. Add the resulting areas ...

How To: Learn Calculus in 20 minutes

Did you sleep all semester in your Calculus class? Are you just waking up now to realize you have a test on Monday and that you're totally screwed? Well, luckily you can learn an entire semester worth of Calculus in just twenty minutes... or at leasts that's the hope.

How To: Rotate a shape about the origin 90° counter-clockwise

Davitily thinks that you can learn to rotate the images quite easily. In this video Davitily explains the process of rotating a geometrical shape about the origin. This rotation is counter-clockwise. Davitily explains the various steps involved in this process. Two steps are explained in this process. The explanation is very simple and done in a very interesting manner. This video is the perfect choice for people wanting to learn the rotation of shapes. This video is a must for people interes...

How To: Find the value of a variable in an algebraic equation

Need help figuring out how to solve simple algebraic equations? Learn how with this free video lesson. 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).

How To: Calculate math without a calculator

Before the calculator and even the abacus was invented, there was a little instrument called the human brain that we used to do math. Remember that? While most of us turn to our trusty Ti-84s to do calculus homework or whip out our cell phone calculators to determine how much we should tip at Johnny Rocket's, it can often be much faster to use our own brains, along with a piece of paper and pencil.

How To: Calculate weight if given the mass

The video shows how to calculate weight if the mass is given and vice versa.Later on in this unit you will learn about Newton's laws of motion and Newton's second law of motion gives us a way to change mass into weight and vice versa.This law will tell you what is happening to objects when the net force on the object is not equal to zero and the easy way to say what will happen is that the object will accelerate.But how much the object accelerates depends on two things,firstly the mass of the...

How To: Simplify fourth roots

In this video the instructor shows how to find out the fourth roots of a number. The properties of fourth root says that for any positive number of a, its fourth roots are real. And for any negative value a, its fourth roots are not real. So split the number inside the fourth root as the product of two perfect squares and then cancel out the power with the fourth root giving its roots. As the fourth roots of a positive number are real, the answer you get is correct. But you cannot find out th...

How To: Identify characteristics of a sample during a survey

To identify characteristics of a sample in your survey, there are many factors to consider of your samples. The first four characteristics you need to focus on are gender, age, income level, and education level. All four of these characteristics must be proportional to that of the population. You also need to consider the geographic location. Only take samples from the immediate geographical area. Finally, an important characteristic of the survey is the sample size. You do not want to ask to...

How To: Find the average value of a function over an interval

When you have to find the average of two or five numbers then you have to add all the numbers and then divide then by two or five respectively. However in the case of the function you have infinite many values over any interval. But it is not possible to add all and then divide by infinity. Therefore you have to calculate in a different way. Imagine that you have to find the average of y=f(x). Then you have to average it from the interval from ‘a’ to ‘b’. The inner area under the curve shall ...

How To: Calculate percent error in chemistry lab activities

If you want to know how to calculate percent error easily, you should watch this video. Error is the amount of deviation from accurate values. Error calculation is not possible, unless you make a quantitative measurement of the various quantities involved in your experiment. Measurement can help us in calculating errors and knowing how right we are in our theoretical models. In calculating percent error, We need to get the experimental value and the value which you are aiming at, which is the...

How To: Translate a shape

Learn how to translate shapes with a few simple steps. - First step: Find the new verticals under the transformation which are T3,2. Values are A=(-5,-8), B=(-3,-4), C=(-8,-3), D=(-6,1). Find the points of the verticals on the graph and connect the points one by one until you can get one shape.

How To: Use the ratio formula to find coordinates of a point

This video is recorded in a mathematics class room. It is very clear by the sound and picture. The faculty here is explaining that the ratio between two numbers can be found using various formulae and methods. For example, 3:1 is the ratio between p and q. Likewise he explained the other formulae and methods.

How To: Write a logarithm as a sum or difference of logarithms

This video shows the method to write a logarithm as a sum or difference of logarithms. The square root of the term given is taken out as half according to the rule. Then the numerator and denominator is divided into product of factors. This is broken into the difference of numerator and denominator according to the rule. Finally, the product of factors is expressed as the sum of factors. Now we see the domain of the term. As the term is a square root of the term it should be greater than zero...

How To: Do long division with decimals

Video Nerd thinks that when your doing long division with decimals you should first take out the decimal. Write the number as if it didn't have a decimal. For example if the problem was 12.5 divided by 5 then you will just use 125 and divide that by 5. Next divide the first digit of the dividend by the divisor an write the number up top. Next you multiply, after your done multiplying the numbers subtract, and when your done subtracting the numbers drop the reaming numbers in the dividend down...

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: Evaluate square roots

This is the video about how to evaluate square roots. The square root of a number is a number that you can square to get it, that is, a number that you can multiply by itself to get the number. So, 2 is a square root of 4, because 2 x 2 = 4, and 3 is a square root of 9, because 3 x 2 = 9. (-2) x 2 is also 4 and (-3) x 2 is also 9. Numbers that have square roots always have two, a positive one and a negative one, but the square root symbol means only the positive one, so we can have one answer...

How To: Solve word problems involving domain and range

See how to find the domain and range of a function implied by a word problem with this free video math lesson. 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 tutor...

How To: Simplify fractions with variables in basic algebra

Need help reducing fractions containing algebraic variables? Learn how with this free video lesson. 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).

How To: Graph x & y intercepts on a TI-84 Plus calculator

In this video the teacher shows us how to use a TI-84 plus graphing calculator to graph a function, adjust the view window, and determine the values of several types of critical points on the graph such as x-intercept, y-intercept, local maximums, and local minimums. After entering the function in the Y= editor she presses the ZOOM button and selects Z-Standard this adjusts the view window to a range of -10 to 10 on both axis. To find each of the critical points requested the teacher uses the...

How To: Simplify surds (improper square roots)

Could you use a little help figuring out how to simplify numbers left in square root form? Watch this free video lesson. 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 free math tutorial, you'll learn how to simplify surds.

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.