√324000+√490000-√640000

To calculate the given expression, we need to find the square root of each number and then perform the addition and subtraction.

√324000 = 540 √490000 = 700 √640000 = 800

Now we can substitute these values into the expression:

540 + 700 - 800

This simplifies to:

= 1240 - 800 = 440

Therefore, the answer is 440.