Hi. I was just wondering why in some equations the top (numerator) and bottom (denominator), can either be positive or negative exponents? Let's say, for the example, "Convert 250 mg to kg," - all you need to do is do it in a 3 steps, by going to the base unit(grams).
So you go
250 mg x 10 ^-3 g x 1 kg = 250kg
1 mg 10 ^3 g
But why is the numerator negative for grams and the bottom grams is positive? Can someone answer this please and thanks!


