While doing a problem on his calculator. Tom meant to divide a number by 2, but instead he accidentally multiplied the number by 2. Which of the following calculations could Tom then do to the result on the calculator screen to obtain the result he originally wanted?

Options

A. Subtract the original number
B. Multiply by 2
C. Multiply by 4
D. Divide by 4

Answer

To solve the problem step by step, let's denote the original number Tom intended to work with as \( x \).

### Step 1: Identify what Tom intended to do
Tom meant to divide the number \( x \) by 2. Mathematically, this can be expressed as:
\[ \text{Intended result} = \frac{x}{2} \]

### Step 2: Identify what Tom actually did
Instead of dividing by 2, Tom accidentally multiplied the number \( x \) by 2. This can be expressed as:
\[ \text{Actual result} = 2x \]

### Step 3: Determine how to get to the intended result from the actual result
To find out how Tom can get back to the intended result from the actual result, we need to manipulate \( 2x \) to reach \( \frac{x}{2} \).

### Step 4: Find the operation to perform
To find the relationship between \( 2x \) and \( \frac{x}{2} \), we can set up the equation:
\[ \text{Desired result} = \frac{x}{2} \]

To transform \( 2x \) into \( \frac{x}{2} \), we can divide \( 2x \) by 4:
\[ \frac{2x}{4} = \frac{x}{2} \]

### Conclusion
Thus, to obtain the result he originally wanted, Tom should divide the result on the calculator screen (which is \( 2x \)) by 4.

### Final Answer
The correct option is: **Divide by 4.**

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