The sum of largest 6-digit number and smallest 6-digit number is ______ .

Options

A. 100000
B. 1999999
C. 99999
D. 1099999

Answer

To find the sum of the largest 6-digit number and the smallest 6-digit number, we can follow these steps:

### Step 1: Identify the largest 6-digit number
The largest 6-digit number is made up of all 9s. Therefore, the largest 6-digit number is:
\[ 999999 \]

### Step 2: Identify the smallest 6-digit number
The smallest 6-digit number cannot start with 0 (as it would then not be a 6-digit number). The smallest valid 6-digit number is:
\[ 100000 \]

### Step 3: Calculate the sum of the largest and smallest 6-digit numbers
Now, we will add the two numbers we identified:
\[ 999999 + 100000 \]

### Step 4: Perform the addition
Let's perform the addition step by step:
- Start from the rightmost digit:
- \(9 + 0 = 9\)
- \(9 + 0 = 9\)
- \(9 + 0 = 9\)
- \(9 + 0 = 9\)
- \(9 + 0 = 9\)
- \(9 + 1 = 10\) (write down 0 and carry over 1)

Putting it all together, we have:
\[ 999999 + 100000 = 1099999 \]

### Final Answer
The sum of the largest 6-digit number and the smallest 6-digit number is:
\[ \boxed{1099999} \]

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