find the value of `9998xx999=?`

Options

A. 9997001
B. 9988002
C. 9987012
D. 9898012

Answer

To find the value of \( 9998 \times 999 \), we can use a mathematical approach that simplifies the multiplication. Here’s a step-by-step solution:

### Step 1: Rewrite the numbers
We can express \( 9998 \) and \( 999 \) in a way that makes multiplication easier. We can write:
\[ 9998 = 10000 - 2 \]
\[ 999 = 1000 - 1 \]

### Step 2: Use the distributive property
Now we can use the distributive property (also known as the FOIL method for binomials) to expand the multiplication:
\[ 9998 \times 999 = (10000 - 2) \times (1000 - 1) \]
This expands to:
\[ = 10000 \times 1000 - 10000 \times 1 - 2 \times 1000 + 2 \times 1 \]

### Step 3: Calculate each term
Now we calculate each term:
1. \( 10000 \times 1000 = 10000000 \)
2. \( 10000 \times 1 = 10000 \)
3. \( 2 \times 1000 = 2000 \)
4. \( 2 \times 1 = 2 \)

Putting it all together, we have:
\[ 9998 \times 999 = 10000000 - 10000 - 2000 + 2 \]

### Step 4: Combine the results
Now we combine the results:
\[ 10000000 - 10000 = 9990000 \]
\[ 9990000 - 2000 = 9988000 \]
\[ 9988000 + 2 = 9988002 \]

### Final Answer
Thus, the value of \( 9998 \times 999 \) is:
\[ \boxed{9988002} \]

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