If a company produces phones and earns $32 million in sales but pays $24 million for the items sold, then the company's gross profit margin would be ($32M - $24M) / $32M = 25 percent.
Burning legs can result from a number of causes, including damage to nerves in the legs from exposure to extreme heat or cold or to toxic substances. Burning legs might also result from a circulation problem that impairs blood flow to the legs, a leg injury, or intense exercise.
Chronic conditions, such as multiple sclerosis, can also cause the sensation of burning in the legs. Alternatively, burning legs may be caused by peripheral neuropathy, a disorder in which the peripheral nerves that relay signals between the body and the brain and spinal cord lose function.