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Marcella wrote an expression for a number trick. \begin{tabular}{|c|} \hline Marcella's Trick \\ \hline\(\frac{4(x-5)+8}{2}-x+6\) \\ \hline \end{tabular} a. Describe Marcella's number trick in words. b. Pick a number and use it to do the trick. What answer do you get? Pick another number and do the trick again. What is the "trick"?

Short Answer

Expert verified
Marcella's trick always returns the original number.

Step by step solution

01

Translate the Expression into Words

Let's break down Marcella's trick into a sequence of mathematical operations. The expression is: \( \frac{4(x-5)+8}{2}-x+6 \). In words, this translates to:1. Pick a number \( x \).2. Subtract 5 from \( x \).3. Multiply the result by 4.4. Add 8 to the result.5. Divide the total by 2.6. Subtract the original number \( x \).7. Add 6 to the result.This sequence captures Marcella's number trick.
02

Execute the Trick with a Sample Number

Let's choose \( x = 10 \) as the first sample number.1. Subtract 5: \( 10 - 5 = 5 \).2. Multiply by 4: \( 5 \times 4 = 20 \).3. Add 8: \( 20 + 8 = 28 \).4. Divide by 2: \( \frac{28}{2} = 14 \).5. Subtract original \( x \): \( 14 - 10 = 4 \).6. Add 6: \( 4 + 6 = 10 \).So for \( x = 10 \), the result is 10.
03

Execute the Trick with Another Number

Now, let's choose \( x = 7 \) as a second sample number.1. Subtract 5: \( 7 - 5 = 2 \).2. Multiply by 4: \( 2 \times 4 = 8 \).3. Add 8: \( 8 + 8 = 16 \).4. Divide by 2: \( \frac{16}{2} = 8 \).5. Subtract original \( x \): \( 8 - 7 = 1 \).6. Add 6: \( 1 + 6 = 7 \).So for \( x = 7 \), the result is 7.
04

Identify the Trick

Repeat the calculations or analyze the expression after simplifying it. Let's simplify it:1. Start: \( \frac{4(x-5)+8}{2}-x+6 \).2. Distribute inside the parentheses: \( 4x - 20 \).3. Add:\( 4x - 20 + 8 = 4x - 12 \).4. Divide by 2: \( \frac{4x - 12}{2} = 2x - 6 \).5. Subtract \( x \): \( 2x - 6 - x = x - 6 \).6. Add 6: \( x - 6 + 6 = x \).This means that the final result is equal to the original number \( x \). Hence, the "trick" always returns the original number.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Number Operations
Understanding number operations is crucial in this exercise. They form the building blocks of more complex mathematical expressions. In Marcella's number trick, we perform several number operations in sequence.
  • **Subtraction:** We start by taking a number \( x \) and subtracting 5. This is a basic arithmetic operation that reduces the value of \( x \).
  • **Multiplication:** Next, we multiply the result by 4. Multiplication is a way to repeat addition quickly.
  • **Addition:** After that, we add 8 to the result. Addition increases the value, bringing us a step closer to the resulting expression in the trick.
  • **Division:** We then divide the sum by 2, which shares or distributes the total into 2 equal parts.
  • **Subtraction and Addition Combination:** Towards the end, more subtraction with \( x \) and addition of 6 follows. These complete the transformation sequence in the trick.
Throughout Marcella's trick, these operations are the fundamental tools that manipulate the initial number \( x \) to unveil the trick's outcome.
Simplification
Simplification in mathematics involves condensing expressions into a simpler form without changing their value. By simplifying Marcella's trick algebraically, we make it clearer and easier to understand.Let's walk through the simplification of Marcella's expression: 1. **Distribute the Terms:** Begin with distributing the 4 across \((x - 5)\), which gives us the expression \(4x - 20\).2. **Combine Like Terms:** Add the constant 8 to \(-20\), resulting in \(4x - 12\).3. **Simplify Fractions:** Divide the entire expression by 2 leading to \(2x - 6\).4. **Simplifying Further:** Subtract \(x\) from \(2x\) gives \(x - 6\).5. **Final Simplification:** Finally, by adding 6, the expression resolves back to \(x\).This shows that the operations in the trick don't change the value of \(x\); they merely cycle through a series of manipulations that ultimately return \(x\) itself. Recognizing these simplification steps is a powerful skill, as it allows you to decode complex expressions wisely.
Mathematical Tricks
Mathematical tricks like the one created by Marcella often involve clever use of operations to transform numbers. The underlying goal is usually to amaze, entertain, or reinforce understanding of mathematical operations.- **Purpose:** They demonstrate interesting properties of numbers or operations, like how a cycle of steps can bring you back to your starting point.- **Conceptual Understanding:** Marcella's trick offers insight into inverse operations. For example, when you add and then subtract the same value, you cancel each other out.- **Application:** Tricks are used in puzzles and magic tricks, sharpening problem-solving skills and creative thinking.When breaking down Marcella's trick, we see that each step's design leads to the surprise result: the return of the original number \(x\) no matter what \(x\) you begin with. This elementary yet intriguing aspect of mathematical tricks makes studying them both enjoyable and educational.

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