4 US tons (short tons) is 8000 pounds (1 ton = 2000 pounds) For the Imperial or long ton (2240 pounds), 4 tons would be 8960 pounds. For the metric ton (1000 kilograms, 2204.62 pounds), 4 tonnes is about 8818.4 pounds.
Convert everything to pounds. Four tons is 8,000 pouns and one tons is 2,000 pounds. So 4 tons 300 pounds is 8,300 pounds. One ton 500 pounds is 2,500 pounds. Now subtract...8,300-2,500=5,800 pounds. Now divide by 2,000 to get tons again...5,800/2,000=2.9. So the answer is two tons, 900 pounds.
4,000,000 pounds are equal to 2000 short tons, which is the US accepted measurement. For the International Standard equivalent, the answer is 1,814.36 tonnes. The International Standard measurement is based off of the kilogram, where as the US Standard measurement is based off of the pound.