# Hot Math How-Tos

### How To: Remember "greater than" & "less than" symbols

This video shows you how to easily remember "greater than" and "less than" math symbols. The first thing you have to remember is that "less than" symbol looks like the letter L ("less than" symbol is "<"). When you see this sign, remember that < looks like L and means "less than". The other symbol, "greater than" does not look like the letter L, therefore it cannot be "less than" and it's easier to remember. The "greater than" symbol is ">". That's it! Good Luck!

### How To: Use ">" (greater than) and "<" (less than) symbols

In this video the author explains how to identify the less than (<) and greater than (>) symbols and when to use them. She explains to us to relate the numbers to animals stating that the smaller numbers are smaller animals and bigger numbers are bigger animals. Now she tells us to imagine that smaller animals are eaten up by the larger animals. So she shows a smaller number comes on the left side of '<' sign and bigger number comes on the right side of '<' sign stating that the bigger number...

### How To: Do long division without a calculator

This video shows you step by step how to do long division without the use of a calculator. The video shows viewers two different ways to solve a division problem. It first shows how to do the problem the traditional way, then it shows how to do it according to the long division process. The long division process is where you write the whole division, multiplication, and subtraction process out showing all your work. Long division is mainly used when dividing large numbers. There are three com...

### How To: Find the Slope Given 2 Ordered Pairs

Slope is the change in Y over the change in X. Written out, the formula looks is as follows: (y2-y1)

### How To: Figure out the domain & range of a piecewise function

Need to calculate the domain and range of a graphed piecewise function? 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: Find Leg Lengths and Hypotenuse of a 45 45 90 Triangle

A 45 45 90 triangle is a special right triangle because you can use short cuts to find leg length and hypotenuse length. This video solves two problems involving leg length and hypotenuse length.

### How To: Convert improper fractions to mixed numbers quickly

Watch this video to learn how to convert improper fractions to mixed numbers. For example, follow these steps. First step is one fraction value. For example 7/3. Second step is divide the numerator by denominator means when 7 divide 3 you can get remainder as 1. Means 7 before value can multiply with the 6 so you can subtract 7-6=1 that is remainder. Multiplied value of 3 nothing but 2 is multiplication of the mixed numbers remainder take it as a numerator and denominator is always take it as...

### 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 a missing side of a triangle, similar to another

In this tutorial the author shows how to find out the missing side of a triangle which is similar to an other triangle. He explains the concept of similar triangle using diagrams and by showing that similar triangles have equal corresponding angles and parallel sides. Now he labels sides of similar triangles and intends to find out the length of unknown side. Now in similar triangles, as the lengths of sides are proportionate he shows how to write a equation of proportion and solve it finding...

### How To: Solve for the missing ratios or proportions

In this video the tutor shows how to solve the missing ratios or proportions. He explains it with an example, where a number in one of the ratios is missing and he intends to find this value. He shows the example of cross multiplication, where you multiply the values on the either side of the equation diagonally and finally solves the equation which results in the value of the unknown value. This is an introductory video explaining how to use rations and proportions to find missing values.

### How To: Convert between diameter and radius

To convert between diameter and radius just follow a few steps. Sometimes we aren't given the number directly so first we need to find the diameter.

### How To: Write a slope-intercept equation given an X-Y table

In this tutorial the author shows how to derive a slope-intercept equation of a line given an X-Y table. He explains that the general form of slope intercept form which is y = m*x + b. Now he intends to find value of slope, i.e. m first. Now slope is change in y over change in x. He computes the slope using the X-Y values from the table. Next he substitutes a pair of x, y value in the equation to compute the value of y intercept b. Now finally substituting the values in the equation the slop-...

### How To: Find the slope of a line given 2 points with fractions

In this video tutorial the instructor shows how to find the slope of a line given two points with fractional values. To do this first name your two points as point 1 with coordinates as x1, y1 and point 2 with coordinates x2, y2. Then substitute the values in the equation of the slope which is slope m = (y2 - y1) / (x2 - x1). Now all you have to do is simply the fraction after substituting the point values. Be careful about the signs while substituting in the formula. Now finally after solvin...

### How To: Find a slope of a straight line with: Ax + By + C = 0

In this video the instructor shows how to find the slope of an equation which is in the form Ax + By + C = 0. He says that the formula to find the slope of a line in the above form is slope m = -A/B, where A and B are the numeric constants of the variables x and y in the given equation. He goes on and further shows how to do this with a couple of examples. He shows how to reduce any equation into the general form and how to apply the slope formula then. This video shows how to find the slope ...

### How To: Find the slope from a set of points

To find the slope of a line you must have two points and then you must plug in the two points into the slope formula. The slope formula is m= y2-y1 over x2-x1. If the slope is a fraction be sure to reduce to the lowest. Remember if a number is divided into zero it is zero, if zero is divided into the number it is undefined. A calculator can help one remember this. Horizontal lines have slopes and vertical lines do not. Drawing the lines on a graph can help you see the actual slopes and which ...

### How To: Subtract fractions with borrowing

This how-to video describes how to subtract fractions using the borrowing method. The video shows viewers everything they need to know including basic subtraction of fractions, how to find common denominators, to the more difficult borrowing techniques. The narrator in this video does a great job of keeping things simple enough for anybody to understand. At the same time, he goes in depth enough that you really get how to use this technique. The voice in this video is very calm and clear. Thi...

### How To: Use and find x & y-intercepts in algebra

A straight line can be represented in the form of a liner equation containing two variables x and y. When the equation is graphed on a pair of coordinate axes, the line passes cut through the axes in two points. The point where the line cuts the x-axes is called as its x coordinate and the point where the line cuts the y-axes is called as its y coordinate. In this way a line has x-intercept and y-intercept. The x-intercept of a line lies on x axes and is in the form (a,0). Similarly the y-int...

### How To: Solve a system of linear inequalities via elimination

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 a system of linear inequalities by elimination.

### How To: Calculate percent composition for chemistry

To calculate percentage composition we will take the example CO2 it stands for Carbon-Di-Oxide. It is the composition of Carbon and Oxygen. We have one carbon and its weight is 12.01 and 2 oxygen. So, we will multiply 2 with 16.00 which is the weight of the oxygen.

### How To: Find the area & perimeter of triangles & squares

When you are figuring the area of a square, you only need to know the height and width of the shape. Once you know the height and width, multiply them to get the area of the square. To find the perimeter of the square, add all four sides together. To find the area of a triangle, multiply together two of the sides (not the hypotenuse) and then multiply that figure by 1/2. To find the perimeter of the triangle, add all three sides together.

### How To: Find the Volume of Composite Figures (Also Called Composite Shapes)

Composite figures are composed of several geometric shapes and are three-dimensional shapes. The first composite shape is a combination of a rectangular prism and a pyramid. To find the volume of the entire shape you find the volume of each individual shape and add them together. The second figure consists of a cylinder and a hemisphere. Check out the video below for the full lesson.

### How To: Factor a trinomial with negative leading coefficient

In this video the instructor shows how to factor a trinomial with negative leading coefficient. Most of the students are confused when they have to factor a trinomial with a negative leading coefficient. But there are many ways to solve these kind of problems as shown in this video. One way you can do is that take out the greatest common factor (GCF) of -1 from the equation. So pulling the -1 gives you the original trinomial with all the signs of the terms changed. Now go on and factor the ne...

### How To: Calculate the height and volume of a pyramid

Need to know how to calculate the height and volume of a pyramid in geometry? 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: Solve an equation with fractional powers

Solving equations involving fractional powers of a variable are not that hard to solve as they sound. In fact, just watch this video to learn a few tips and solving these type of equations will become a little bit easier.

### How To: Find a missing angle outside of a triangle

For people who are having problems with certain parts of geometry, this video will offer you advice on how to find a missing angle on the outside of a triangle when you are provided with the measurements of the other two angles in the triangle. Since the sum of the angles in a triangle is always 180 degrees, you should first take the sum of the other two angles and then subtract this from 180 in order to find the measurement of the missing angle in the triangle. Next, since there are also 180...

### How To: Convert fractions to percents in two steps

This video shows you how to easily convert fractions to percents. You can convert fractions to percents in 2 easy steps. The first step is multiplying the fraction by 100 (e.g.. your fraction is 3/5; 3/5 x 100 = 3/5 x 100/1 = 300/5). The second step is reducing the fraction, when possible (e.g.. 3/5 x 100/1 = 300/5 = 60). Don't forget to add the percent sign (%)(you obtained 60%). That's it! Good Luck!

### How To: Find a missing coordinate given: coordinate & equation

In this video, the instructor shows how to find an unknown coordinate given the other coordinate of that point and the equation that passes thought the point. A point is said to lie on the graph, if the point can satisfy that equation of the line. To check if a particular point satisfies an equation, all you have to do is substitute the value of the point in that equation and check if it validates the equation. Now, substitute the given point with an unknown coordinate in that equation. If th...

### How To: Square expressions involving radicals

Here we look at squaring expressions that involve radicals because people tend to make some common mistakes while solving such expressions. Take 5 times the square root of y quantity squared, the answer here is not 5y. Here's the reason, square means to multiply something with itself so the square of 5 root y would be 5 root y into 5 root y. So 5 x 5 is 25 and under root y into under root y equals just y so the answer will be 25y.

### How To: Solve problems involving deductive reasoning

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 unpack and solve word problems that require you to apply deductive reasoning.

### How To: Draw a right trapezoid in Geometry

Watch this video to learn how to draw a right trapezoid using given specifications for lengths of sides. A right trapezoid is a four-sided shape with two right angles and two parallel sides. First, draw the long base. Then draw a 90 degree angle at one end of the base, using a protractor. Mark the angle to show it is 90 degrees. Then draw another 90 degree angle at the top. This is the first video in a set--to finish learning you must watch the next segment. If you watch these videos you will...

### How To: Find the area of a circle when you know the diameter

In this video, it is shown how to calculate the area of a circle where the diameter is given. The formula for calculating the area of a circle is pi multiplied by square of radius. Radius is actually half of the diameter. In this video, the diameter is given as 10.6 meters. Hence, the radius will be half of 10.6 which is equal to 5.3 meters. Now, to find the area we shall multiply pi with the square of 5.3. Square of 5.3 is 28.09. If we multiply 28.09 with pi we shall get the area of the circ...

### How To: Find the x & y intercepts of rational functions

In this tutorial the instructor shows how to find the x and y intercepts of rational functions. Finding the intercepts of a rational function is similar to finding the intercepts of other normal equations. You can find the x intercept of the equation by setting the value of y to zero and solving the equation. Similarly you can solve the y intercept by setting the value of x to zero and solving the equation. Now while solving this rational function for intercepts if you face a situation where ...

### How To: Subtract mixed numbers with renaming with Mr Binkley

This video is about subtracting mixed numbers and renaming. 1. Start on the right side of the problem.

### How To: Prove Rank(A) = Rank(transpose of A) in linear algebra

Learn how to prove that the rank of a matrix, A, is equal to the rank of its transpose in linear 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 finish your homework or study for that next big test).

### How To: Interpret a standard deviation

A rough definition of standard deviation is that it is a measure of expressing the observed variations about the average in statistical data i.e. by how much do the observed values vary from the mean. This video continues from the previous solved example and demonstrates the mathematical interpretation of the standard deviation that was calculated. We begin with stating the mean and standard deviation values and then calculating the upper and lower bounds of the data based on the standard dev...

### 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: Graph negative numbers on number line

The video begins with a piece of paper with questions 6 and 7 on from section 1.3. The narrator introduces these two questions as both having to do with graphing on a number line. Starting with question 6, which asks the person to graph -11/4 on a number line, the narrator draws a number line with the numbers up to -5 on the left, up to +5 on the right of 0 in the middle. She starts by showing -3 as an example, and then draws a black dot on the line at the point of the number 3. She then illu...

### How To: Calculate percentage

Not sure exactly how to calculate a twenty percent tip for your waitress? Or how about how to figure out how much less your cost will be with that thirty percent off tag? Use these steps to calculate percentage, without a calculator.

### How To: Calculate and solve for density

Density is a means of representing how much mass is contained in the body of an object. The basic formula is: Density (D) = Mass (M) / Volume (V) so D=M/V. Density is important to know for buoyancy and to understand how heavy an object is. This video will show you three examples of measuring density so you can learn and put it to good use.

### How To: Calculate Faster Than a Calculator

When you need to crunch numbers quickly — and I mean really quickly — there's a cool method you can use to multiply two numbers together in just a few seconds.