The point A on a mountain is 6450 metres above the sea level. Another point B is in a mine 486 metres below the sea level. Find the distance between the two points.

Answer

To find the distance between point A, which is 6450 meters above sea level, and point B, which is 486 meters below sea level, we can follow these steps:

### Step 1: Understand the positions of points A and B
- Point A is at +6450 meters (above sea level).
- Point B is at -486 meters (below sea level).

### Step 2: Calculate the total distance between the two points
To find the distance between the two points, we need to add the absolute values of their positions since one is above sea level and the other is below sea level.

### Step 3: Set up the equation
The distance between the two points can be calculated as:
\[ \text{Distance} = \text{Distance from A to sea level} + \text{Distance from sea level to B} \]
\[ \text{Distance} = 6450 + 486 \]

### Step 4: Perform the addition
Now, we will add the two distances:
- First, add the units: 0 + 6 = 6
- Next, add the tens: 5 + 8 = 13 (write down 3 and carry over 1)
- Then, add the hundreds: 4 + 4 + 1 (carry) = 9
- Finally, add the thousands: 6 + 0 = 6

Putting it all together, we get:
\[ 6450 + 486 = 6936 \]

### Final Answer
The distance between point A and point B is **6936 meters**.

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