Up-and-Down Staircase:
One block is needed to make an up-and-down staircase, with one step up and one step down.
4 blocks make an up-and-down staircase with 2 steps up and 2 steps down.
How many blocks would be needed to build an up-and-down staircase with 5 steps up and 5 steps down?
Explain how you would work out the number of blocks needed to build a staircase with any number of steps.
