Matilda throws a dice 70 times work out the estimate for the number of sixes she should expect to throw

So she is finding an experimental probability.

experimental probability = (number specific outcomes observed) / (total observations)

In this case:

ep = (number of sixes rolled) / (number of rolls)

ep = (number of sixes rolled) / 70

After she calculates the expected probability then she would approximate the number of expected sixes to be rolled by:

ep*rolls = (expected number of sixes rolled in n rolls)

It would be about 12 times