excel formula help

I am trying to enter a formula that will calculate:

One cell has a range of weights: 1 thru 500
501 thru 1000
1001 thru 2000
2000 >

I need to * the ranges above by a number that corresponds to the applicable weight.

ex: 1 thru 500 * 10
501 thru 1000 * 12

I need the amount (weight) that is a sum from another sheet to be the exact # between the ranges. Ex; 535 * 12