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Subtraction - Grade 3 Common Core Standards
By shaunteaches
In this question, we show several methods for subtracting
Example 4: Adding and subtracting polynomials | Algebra I | Khan Academy
By Khan Academy
This video is from Khan Academy. It demonstrates the proper method of adding and subtracting polynomials
[5.NBT.7-1.0] Operations on Decimals - Common Core Standard
By Front Row
Discover more Common Core Math at https://www.frontrowed.comAdd decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.Front Row is a free, adaptive, Common Core aligned math program for teachers and students in kindergarten through eighth grade. Front Row allows students to practice math at their own pace - learning advanced concepts when they're ready and receiving remediation when they struggle. Front Row provides teachers with access to a detailed data dashboard and weekly email reports that show which standards are causing students difficulty, what small groups can be formed for interventions, and how their students are progressing in math.Discover more Common Core Math at https://www.frontrowed.com
[5.NBT.7-3.0] Operations on Decimals - Common Core Standard
By Front Row
Discover more Common Core Math at https://www.frontrowed.comMultiply decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.Front Row is a free, adaptive, Common Core aligned math program for teachers and students in kindergarten through eighth grade. Front Row allows students to practice math at their own pace - learning advanced concepts when they 're ready and receiving remediation when they struggle. Front Row provides teachers with access to a detailed data dashboard and weekly email reports that show which standards are causing students difficulty, what small groups can be formed for interventions, and how their students are progressing in math.Discover more Common Core Math at https://www.frontrowed.com
Synthetic Division | MathHelp.com
By MathHelp.com
In this example, it’s tempting to divide x squared + 5x – 6 by x + 1 by first factoring x squared + 5x – 6. The factors of -6 that add to positive 5 are +6 and -1, so we have x + 6 times x – 1 over x + 1. Notice, however, that nothing cancels. In this situation, we need a different method of dividing the polynomials, so we use long division. In other words, we rewrite x squared + 5x – 6 divided by x + 1 as x + 1 divided into x squared + 5x – 6. Now, our first step in the long division is to determine how many times x goes into x squared. Since x goes into x squared x times, we write an x above the x squared, just like we do with regular long division. Next, we multiply the x times the x + 1 in the divisor to get x squared + x, and we write the x squared + x underneath the x squared + 5x. Next, we subtract x squared + x from x squared + 5x. And watch out for this step: it’s an area where most of the common mistakes in these types of problems are made. Instead of subtracting, I would change the sign of each term in x squared + x, so we have negative x squared + negative x, then add the columns. So we have x squared + negative x squared, which cancels out, and positive 5x + negative x, which is positive 4x. Next, we bring down the -6, in regular long division. Now, we need to determine how many times x goes into 4x. Since x goes into 4x 4 times, we write a positive 4 in our answer. Next, we multiply positive 4 times x + 1 to get 4x + 4, and we write the 4x + 4 underneath the 4x – 6. Next, we subtract 4x + 4 from 4x – 6. In other words, we change the signs on 4x + 4 to -4x + -4, and we add. 4x + -4x cancels out, and -6 + -4 is -10. And since there are no other numbers to bring down, we have a remainder of -10. Finally, remember from the previous example that we add the remainder over the divisor to the quotient. In other words, we add -10 over x + 1 to x + 4, and we have x + 4 + -10 over x + 1. So x squared + 5x – 6 divided by x + 1 simplifies to x + 4 + -10 over x + 1.
Qtr 2, Lesson 3: Writing Systems of Linear Equations
By Stan Lisle
How to solve problems using two equations and two variables.
Total seats in a theater | Multiplication and division
By Khan Academy
Solve a two-step word problem by drawing a picture and creating an equation.
Marbles for friends | Multiplication and division
By Khan Academy
Solve a two-step estimation word problem.
Running distance in a week | Multiplication and division
By Khan Academy
Solve a two-step word problem by drawing a picture and creating an equation.
Adding and Subtracting Polynomials | MathHelp.com
By MathHelp.com
In this example, notice that each of our variables, x, y, and z, appears in all three equations. To solve this system, we use the addition method. In other words, let’s start with our first two equations, x + y + z = 4, and x – y + z = 2. Notice that if we add these equations together, the +y and –y will cancel out, and we have 2x + 2z = 6. So, in our new equation, 2x + 2z = 6, we’ve eliminated the variable y. Unfortunately, we still haven’t solved for any of our variables. However, if we can create another equation with just x and z in it, then we’ll have a system of equations in two variables, which we can use to solve for x and z. To create another equation with just x and z in it, we need to eliminate y. We can’t add the first and second equations together, because we’ve already done that. However, notice that if we add the first and third equations together, the first equation has a +y and the third equation has a –y, so we’ll be able to eliminate the y. So we have our first equation, x + y + z = 4, and our third equation, x – y – z = 0, and adding them together, notice that the +y – y cancels out, and, as a bonus, the +z – z also cancels out, so we have 2x = 4, and dividing both sides by 2, x = 2. Now, since we know that x = 2, notice that if we plug a 2 in for x in the equation that we created earlier, we can solve for z. And we have 2(2) + 2z = 6, or 4 + 2z = 6, and subtracting 4 from both sides, we have 2z = 2, and dividing both sides by 2, z = 1. So x = 2 and z = 1, and to find the value of y, we simply plug our values of x and z into any of the equations in the original system. Let’s use the first equation, x + y + z = 4. Since x = 2 and z = 1, we plug a 2 in for x and a 1 in for z, and we have 2 + y + 1 = 4, or 3 + y = 4, and subtracting 3 from both sides, y = 1. So x = 2, y = 1, and z = 1, and finally, we write our answer as the ordered triple, x, y, z, or (2, 1, 1).
How many truffle eating guests attended a party
By Khan Academy
Solve a two-step word problem by drawing a picture and creating an equation.
Fractions are Division
By mathantics
A fraction is just a division problem written like a number. This video also reviews the parts of a fraction and introduces the idea of decimals.
Introduction to Division
By northstar15
Learn the basics of division including vocabulary and how to solve simple division problems. A teacher is using a whiteboard to explain the process as well as the vocabulary. He demonstrates two ways to write these division problems. Sound quality is poor.
