1000×n=630
i can't understand this ,

To solve for n?
If yes, then to get n by itself you should get rid of a 1000 by dividing everything by it on both sides. n=630÷1000 n=0.63. Check: 1000×0.63 really does equal to 630. Hopefully that's what you were asking.

=1000 * n = 630
= n = 630 / 1000 (i took n to 1 side and the rest to the other so 1000* becomes 1000/)
= n = .63

now to verify 
.63 * 1000 = 630