Complete the Equation: Finding the Missing Number in 1000 + □ = 2000

To solve the equation $1000 + \Box = 2000$, we will start by isolating the box ($\Box$). This can be achieved by subtracting 1000 from 2000:

• Step 1: Rearrange the original equation to solve for $\Box$:
• Step 2: Calculate $\Box = 2000 - 1000$.

Performing the subtraction:

$\Box = 2000 - 1000 = 1000$

This calculation shows that the missing number is $1000$.

Finally, let's confirm our solution by substituting this value back into the original equation: $1000 + 1000 = 2000$. The equation holds true, verifying our result.

The correct answer is clearly option 4: $1000$.