Hot Math How-Tos

How To: Combine like terms

In order to combine like terms, you need to look at the variables. Terms can only be combined if the variables are all identical. The first thing that you would have to do is look for matching variables. In the example, x + 2x5 + y2 - 9x - 2x5 + 5y2, you should try to see which ones match. Then, group them together. Match the x's with the x's and the y's with y's. Therefore x - 9x = - 8x. 2x5 - 2x5 = 0. Y2 + 5y2 = 6y2.

How To: Rewrite expressions with the distributive law of multiplication

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 problems requiring you to rewrite and simplify an expression with th...

How To: Write a multiplication problem in exponential notation

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 multiplication problem as an exponent problem.

How To: Follow the order of operations in basic mathematics

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 problems requiring use of multiple mathematical operators at once.

How To: Solve rounding problems in basic mathematics

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 problems requiring you to round whole numbers.

How To: Solve word problems that require you to compare whole numbers

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 problems requiring you to compare two or more whole numbers.

How To: Solve word problems involving the addition of whole numbers

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 problems requiring you to add whole numbers.

How To: Rewrite an addition problem as a multiplication problem in math

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 problems requiring you to multiply whole numbers.

How To: Solve word problems that involve rounding to estimate differences

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 problems that require you to estimate differences by rounding.

How To: Solve word problems involving the division of whole numbers

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 divide whole numbers.

How To: Solve math problems involving the identity property of one

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 requiring use of the identity property of 1.

How To: Solve math problems with the commutative law of addition

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 requiring use of the commutative law of addition.

How To: Solve math problems with the commutative law of multiplication

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 requiring use of the commutative law of addition.

How To: Solve math problems with the associative law of addition

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 requiring use of the associative law of addition.

How To: Solve math problems with the associative law of multiplication

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 problems requiring use of the associate law of multiplication.

How To: Match exponential graphs

This video tutorial belongs to the Education category which is going to show you how to match exponential graphs. The video shows two graph sheets with three graphs marked A to F on each sheet and six equations. It starts off with matching the basic function, y = 2 to the power x. If you plug in zero for x, you get '2 to the power 0' which is 1. Hence, the equation becomes; y = 1. So, the graph that passes through y = 1 is the matching one. In the video it is graph A. You can watch the video ...

How To: Find the circumference of a circle

In this video tutorial, viewers learn how to find the circumference of a circle. This task is very easy, simple and fast to do. To find the circumference of a circle, multiple Pi with the diameter of the circle. The value of Pi is 3.14. The diameter is equal to 2 times the radius. Simply multiply the radius by 2 to find he diameter. The diameter is the straight horizontal line in the center of a circle. This video provides a demonstration for viewers to easily understand and follow along. Thi...

How To: Reduce and simplify fractions

In this tutorial, we learn how to reduce and simplify fractions. When you do this, you want to make sure you have taken common factors out of the top and bottom, then divide them out until the only common factor is the number one. You will keep going until you get to this point, or you can do another method by finding the greatest common factor. To understand this better, take the example of 24/64. The greatest common factor of these numbers is 8, because it divides evenly into both of them. ...

How To: Divide bigger numbers

In this video, we learn how to divide bigger numbers. As an example, let's say you were dividing 843 by 13. To make this easier, write down the times tables for 13 down and keep adding up. After you do this, see how many times 13 goes into 84. Your table will tell you how many times it goes into the larger number. Thirteen will go into 84 six times, so write six on the top line above the four, then subtract 78 from 84 and write a 6 next to the 4. Now, work out the remainder and when finished,...

How To: Find the area of a rectangle

In this tutorial, we learn how to find the area of a rectangle. First, you will need to know the formula, which is length times width. So, first find the length and width of the rectangle. After this, you will multiply the length and width together. Next, write down the units so you don't forget. When you are finished, you will know the area in just a few easy steps. This is a basic formula that is easy to understand and can be done quickly. When you are finished finding this, make sure you w...

How To: Convert mixed numbers into top heavy fractions

In this video tutorial, viewers learn how to convert mixed numbers to top heavy fractions. This task is very easy, fast and simple. Begin by multiplying the whole number with the denominator and then add the numerator. In the final answer, the numerator will be greater than the denominator. The denominator stays the same and does not change. This video provides several examples and demonstrations for viewers to have a better understanding. This video will benefit those students who are strugg...

How To: Do quadratic equations

In order to work a quadratic equation, you should, first, try to simplify it. Try to move your variable to one side of the equation and the numerical values to the other. For example, in the equation 3n + 5n 2 = 0, you should try to move the 2 to the other side, by adding a positive two to both sides. Then, you should add together the like variables. This will give you 8n = 2. Then, you will need to divide both sides by 8. The answer will be n = 2/8. The quadratic formula is ax2 + bx + c = 0....

How To: Perform short division

In this Education video tutorial you will learn how to perform short division. The first example is a division by a single digit; 741 divided by 3. You write it as shown in the video and start dividing from the left digit. So, 7 divided by 3 will give 2 with 1 as remainder. Write this down as demonstrated in the video. 1 and 4 make 14 and dividing 14 by3 will give 4 and remainder is 2. Now dividing 2 and 1, that is 21 by 3 you get 7. The answer is 247. The next example is 847 divided by 5. 8 ...

How To: "Back out the tax" from a receipt

In this video, we learn how to back out the tax from a receipt. If you have a receipt where you see how much you paid and know the tax rate, except you want to figure out the cost of the item before the tax. First, take the cost of the item including tax and what the tax rate is. To figure out the original price, let x equal the cost of the item. Add the tax to the cost of the item which will equal the cost you paid. Perform the equation 1x+(tax rate)= (total price). After you figure this equ...

How To: Convert Farenheit to Celsius in your head

This video tutorial is in the Education category which will show you how to convert Fahrenheit to Celsius in your head. This method is a good estimate for converting temperatures. However, do not use this for accurate temperature conversions. Let's say you want to convert 22 degree Celsius to Fahrenheit. 1st step is to double the figure, that is, add 22 plus 22 which is 44. Next add 44 with 30, which gives the result 74. So, 22degree Celsius is equal to 74 degree Fahrenheit. Similarly, 32 deg...

How To: Divide fractions with examples

In this Education video tutorial you will learn how to divide fractions with examples. For example let us divide 1/5 with 3/4. This we can do by changing the division sign in to multiplication sign provided we swap the numerator and the denominator of the divisor to get its reciprocal. The equation can now be written as 1/5 x 4/3. Now multiplying the numerators and the denominators, we get the answer as 4/15. So, you can see that division of fractions is the same as multiplication. You only n...

How To: Find the area of a square or rectangle in geometry

In this video tutorial, viewers learn how to find the area of a rectangle. The formula for finding the area of a rectangle is: A= b x h. The base is the horizontal bottom lie of the rectangle and the height is the vertical straight line of the rectangle. Whenever working with area, users must square the unit of measurement. To find the area of a square, multiple the side of the square twice (square it). This video will benefit those student viewers who are struggling with math, and are in nee...

How To: Add unlike fractions using basic math

In order to add unlike fraction, using basic math, you will need to find the lowest common multiples of the denominators. In order to add 5/12 and 1/6, you will need to make the denominators the same. The lowest common multiple, for these fractions is 12.

How To: Simplify complex fractions with variables

In order to simplify complex variables, you must first consider the numerical values separate from the variable. In the case of 24x/48x, you would look at the numbers alone to see if they have any factors. These numbers have the number 6 in common. So, divide it by 6. This will give you 4/8. This still requires some simplification. Two is still a factor for both. So, divide it again by four. This will give you 1/2. Now, if the numerator was raised to the second power, in the original equation...

How To: Know if matrices can be multiplied

In this Education video tutorial you will learn how to know if matrices can be multiplied. If the column of the first and the row of the second match, you can multiply them. For example if, matrix A has 2 rows and 3 columns (A: 2x3) and matrix B has 3 rows and 4 columns (B: 3x4), then you can multiply them. But, if A: 3x2 and B: 3x4, you cannot multiply them. The shape of the resultant matrix will be the shape of the outer numbers. For example, we saw that if A:2x3 and B :3x2, then they can b...

How To: Do long division in your head

In this video, we learn how to do long division in your head. Start off by trying to do a division problem in your head that divides evenly. This will help you start to get used to doing division in your head. If you come across a problem where you have to carry a number, don't forget to remember it. If you can see a pattern in any division problem, you will be able to solve any problem that you come across. This can be used for small division problems as well as extremely long division probl...

How To: Use the Pythagorean theorem

Pythagoras was a smart man, so smart that his mathematical theory is named after him and still used today, more than 2,000 years later: the Pythagorean theorem. It implies that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides. The Pythagorean theorem is a cornerstone of geometry. Here’s how to use it.

How To: Solve an algebraic equation

Math can be tricky, especially when you're trying to decipher algebra. It's a love-hate thing; if you don't love math, then you hate it, and there's no in-between. But it doesn't have to be a pain to solve a few problems. It's actually quite simple once you figure it out. An algebraic equation is an equation that includes one or more variables. These equations can be solved as long as the number of variables does not exceed the number of equations.

How To: Solve permutation & combination word problems

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 invplving permutations and combinations in basic stati...

How To: Determine the probability of dependent events

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 calculate the probability of two dependent events in statistics.

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: Solve statistical word problems involving events

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 involving events and outcomes.

How To: Solve rational expression simplification word problems

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 simplify rational expressions.

How To: Multiply, divide and simplify rational expressions

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 multiply (or divide) and express a...