In science or physics, a KG or kilogram is a mass (m) unit, and an N or Newton is a unit of force (f). On the Earth, the mass of 1KG is about 2.20 pounds, and on the other hand, if something weighs one pound on Earth, it will have a mass of about 0.454 kg.
In mathematics, or calculus, which Isaac Newton established. A KG is a kilogram, and an N stands for Newton but has more to do with weight and is part of the Imperial measurement system devised in Europe and is otherwise known as the metric system.
A kilogram weighs 2.2 pounds, so 1000 KG = 2200 lbs., and one newton is equal to 0.1019716213 kilograms. If you take 1000 KG and divide by 0.101, the answer is 9,900.9900990099, and round up, and you get 1000 kg.