This one is a “mental” exercise; don’t use paper and scissors; just imagine in your mind.
Take a sheet of paper – any size that you happened to have (remember, just imagine this paper). Now fold this sheet of paper in half and now fold it in half again, at right angles to the first fold. Now you have four thicknesses of paper. Now imagine you use scissors and cut through all four thicknesses, right down the middle of the paper, parallel to the first fold you made. Now, imagine, how many pieces of paper do you have now? Don’t get paper and scissors to solve this one – try to picture this in your mind!
You will have 3 pieces of paper after the cut. It won’t matter which direction you make the cut with the scissors – you’ll end up with 3 pieces of paper. Don’t believe it. Now go and get the paper and scissors and actually do this – you’ll see!