How many rows of 9 are in 18

Hi my sisters and brothers can tell me the answer because i don’t understand the question

An ulcer medication has 300 milligrams in 2 tablets. how many milligrams are in 3 tablets?

The edge of a cube was found to be 30 cm with a possible error in measurement of 0.4 cm. use differentials to estimate the maximum possible error, relative error, and percentage error in computing the volume of the cube and the surface area of the cube. (round your answers to four decimal places.) (a) the volume of the cube maximum possible error cm3 relative error percentage error % (b) the surface area of the cube maximum possible error cm2 relative error percentage error %