If you were asked to convert 25 kg to the unit mg, which of the following would be the first fraction used in the conversion?

To convert from one unit to another unit, a conversion factor is needed to multiply to the measurement. For this case, we are to convert from kg to mg. To do this, we first convert it to grams by multiplying 1000/1. Then, we multiply by 1000/1 again to convert it to mg. Therefore, the first fraction we use would be 1000/1.