Question

A coin is tossed six times. What is the possibility of obtaining no heads?

Answer 1

No heads is the same as all tails. So you want
1st coin tails AND
2nd coin tails AND
... etc

Because you want one event AND another set of events, the odds multiply. If we say that a fair coin has a 50/50 chance of being head or tails, we simply multiply up 0.5 6 times

0.5 x 0.5 x 0.5 x 0.5 x 0.5 x 0.5 = (0.5)^6 = 0.015625
which is equivalent to 1 in 64