Multiply :
`7.8xx100`

Answer

To solve the multiplication of \( 7.8 \times 100 \), we can follow these steps:

### Step 1: Write the multiplication
We start with the expression:
\[ 7.8 \times 100 \]

### Step 2: Convert the decimal to a fraction
We can express \( 7.8 \) as a fraction:
\[ 7.8 = \frac{78}{10} \]
So, we can rewrite the multiplication as:
\[ \frac{78}{10} \times 100 \]

### Step 3: Simplify the multiplication
Next, we can simplify the multiplication:
\[ \frac{78 \times 100}{10} \]

### Step 4: Calculate \( 78 \times 100 \)
Now, we calculate \( 78 \times 100 \):
\[ 78 \times 100 = 7800 \]

### Step 5: Divide by 10
Now, we divide \( 7800 \) by \( 10 \):
\[ \frac{7800}{10} = 780 \]

### Final Answer
Thus, the final answer is:
\[ \boxed{780} \]

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