Can someone tell me what is 3/4 • 2 4/12

How do you find p(a and b) if a and b are independent events for two or more actions, such as tossing a coin twice and finding p(heads and heads)? 2. how do you find p(a or b) if a and b are independent events for one action, such as spinning a four-color spinner once and finding p(red or blue)?