Difference between revisions of "2021 Mock AMC 8 Problems/Problem 1"

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(Problem 1)
 
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==Problem 1==
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==Problem==
 
What is the value of <math>1-2+3-4+5-6+7-8+9</math>?
 
What is the value of <math>1-2+3-4+5-6+7-8+9</math>?
  
 
<math>\mathrm{(A)}\ 4 \qquad\mathrm{(B)}\ 5 \qquad\mathrm{(C)}\ 6  \qquad\mathrm{(D)}\ 7 \qquad\mathrm{(E)}\ 25</math>
 
<math>\mathrm{(A)}\ 4 \qquad\mathrm{(B)}\ 5 \qquad\mathrm{(C)}\ 6  \qquad\mathrm{(D)}\ 7 \qquad\mathrm{(E)}\ 25</math>
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==Solution 1==
 
==Solution 1==
 
Since <math>1-2+3-4+5-6+7-8</math> is <math>-4</math>, so we have <math>-4 + 9 = 5</math> Therefore, our answer is <math>\boxed{\textbf{(B) } 5} \qquad</math>
 
Since <math>1-2+3-4+5-6+7-8</math> is <math>-4</math>, so we have <math>-4 + 9 = 5</math> Therefore, our answer is <math>\boxed{\textbf{(B) } 5} \qquad</math>

Latest revision as of 16:05, 16 October 2021

Problem

What is the value of $1-2+3-4+5-6+7-8+9$?

$\mathrm{(A)}\ 4 \qquad\mathrm{(B)}\ 5 \qquad\mathrm{(C)}\ 6  \qquad\mathrm{(D)}\ 7 \qquad\mathrm{(E)}\ 25$

Solution 1

Since $1-2+3-4+5-6+7-8$ is $-4$, so we have $-4 + 9 = 5$ Therefore, our answer is $\boxed{\textbf{(B) } 5} \qquad$