`99 xx 99 = ? `
A.9791
B. 9801
C.9881
D.9901.

Options

A. A
B. D
C. B
D. C

Answer

To solve the problem \( 99 \times 99 \), we can use the formula for squaring a number, which is \( n^2 \). Here, \( n = 99 \).

### Step 1: Identify the formula
The formula for squaring a number \( n \) is:
\[ n^2 = n \times n \]

### Step 2: Calculate \( 99^2 \)
We can calculate \( 99^2 \) directly:
\[ 99^2 = 99 \times 99 \]

### Step 3: Use the identity for squaring numbers close to 100
We can use the identity:
\[ (a - b)^2 = a^2 - 2ab + b^2 \]
Where \( a = 100 \) and \( b = 1 \):
\[ 99^2 = (100 - 1)^2 = 100^2 - 2 \times 100 \times 1 + 1^2 \]

### Step 4: Calculate each term
1. \( 100^2 = 10000 \)
2. \( 2 \times 100 \times 1 = 200 \)
3. \( 1^2 = 1 \)

### Step 5: Combine the results
Now plug these values back into the equation:
\[ 99^2 = 10000 - 200 + 1 = 9801 \]

### Conclusion
Thus, the value of \( 99 \times 99 \) is \( 9801 \).

### Answer
The correct option is **B. 9801**.

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