1000 - X= 387

To solve for X in the equation 1000 - X = 387, we need to isolate X.

First, we'll move 1000 to the other side of the equation by subtracting 1000 from both sides:

1000 - X - 1000 = 387 - 1000 -X = -613

Next, we'll solve for X by multiplying both sides by -1 to make X positive:

X = 613

Therefore, in the equation 1000 - X = 387, X is equal to 613.