Is the difference between hard and easy problems really so important?

And at first it doesn't seem to be such a hard problem.

So it turns out that this is a hard problem, like I said.

The hard problems are often those of control and communication.

It depends on a number of hard problems, first among them population.

But at home he is determined only to avoid the hard problems.

The reason we're here is to solve the hard problems.

That is also a hard problem, though I think progress has been made.

It's a hard problem, but those are always the interesting ones.

These are all hard problems for a computer to solve.