Boyle's law : For a fixed mass of gas at constant temperature, the volume is inversely proportional to the pressure.

it means the volume is inverse proportion with pressure. Like if you increase the pressure 10 times its volume with be decrease 10 times.

The mathematical expression is PV=constant.  

Charles' Law : For a fixed mass of gas at constant pressure, the volume is directly proportional to the kelvin temperature.

if you twice the kelvin heat from,  like to 200 K to 400 K, the volume of a secure mass of the gas will twice over too.

The mathematical expression is V = constant x T.