30 g serving of a certain breakfast cereal has 0.5 g of salt. The amount of salt is _____________milligrams.

The correct answer is: 500mg

Quantity of salt = 0.5g
We know, 1g = 1000mg
0.5g = 1000 × 0.5
= 500mg
So, salt in milligrams would be 500mg

One g is equal to 1000 mg. therefore, 0.5 g = 0.5 x 1000 mg = 500 mg.