Why do we make mistakes?

Because humans arent the brightest

how do you know your mistakes

If the value of x in the answer does not make the original equation true, then there’s a mistake somewhere. This means that checking whether or not your value of x makes the original equation true greatly reduces the frequency of mistakes on homework and tests.

how would you know about your mistake

You can find out if you made a mistake if your answer doesn't not make the original equation true.

This page has multiple problems - which one are you asking about? Please clarify your question if you need help.

K i understand this but some you have to work out on paper and i dont have paper to use :\ so how am i suppose to work it out without paper?

on the bottom left cornerish of your page wile doing the test thing theirs a little pen that you press on and you can draw it out.

Main content

Operations and Algebraic Thinking 218-221

Course: Operations and Algebraic Thinking 218-221 > Unit 5

Lesson 5: Finding mistakes in one-step equations

Finding mistakes in one-step equations

CCSS.Math:

6.EE.B.7

Google Classroom

Gain a deeper understanding of solving one-step equations by studying a correct and an incorrect example.

Solving one-step equations is all about using inverse operations on both sides of an equation to get the variable by itself. Answer the questions below to deepen your understanding of how to solve one-step equations.

Cam solved this problem start text, start color #1fab54, c, o, r, r, e, c, t, l, y, end color #1fab54, end text:

Solve for x:

\qquad\begin{aligned} 3x&=12\\\\ \\ \dfrac{3x}3&=\dfrac{12}3&\\\\ \\ x&=4&\\\\ \end{aligned}

Why couldn't Cam just subtract 3 to get the x by itself?

(Choice A)
He could have!
(Choice B)
Because 3 and x are added together, and the inverse operation of addition is multiplication, not subtraction.
(Choice C)
Because 3 and x are multiplied together, and the inverse operation of multiplication is division, not subtraction.

Brooke solved this problem start text, start color #e84d39, i, n, c, o, r, r, e, c, t, l, y, end color #e84d39, end text:

Solve for n:

\qquad\begin{aligned} n+4&=5\\\\ \\ n+4+4&=5 +4&\\\\ \\ n&=9&\\\\ \end{aligned}

Why is Brooke's work incorrect?

(Choice A)
She should have been working to cancel out the 5, not the 4.
(Choice B)
n and 4 are added together, and the inverse operation of addition is subtraction. So, she should have subtracted 4 from both sides instead of adding 4 to both sides.
(Choice C)
n and 4 are added together, and the inverse operation of addition is division. So, she should have divided by 4 on both sides instead of adding 4 to both sides.

Solve a problem on your own

Solve for k:

k, plus, 4, point, 2, equals, 5, point, 9

k, equals

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Later in algebra, you will encounter two-step equations and then equations with more than two steps, including equations with parentheses and/or the variable on both sides. A strong understanding of one-step equations will help you solve multi-step equations later on.
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