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The picture above shows four equal weights on one side of the scale and an apple on the other side.
What can you say that is true about the apple and the weights?
If the apple weighs $180g$, how heavy must one weight be?
If the apple weighed $375g$, how heavy would one weight be?
If the apple was a giant one and weighed a full kilo and the weights were each $250g$, what would the scale look like? How do you know? Can you prove it?
Mr. Sunshine tells the children they will have 2 hours of homework. After several calculations, Harry says he hasn't got time to do this homework. Can you see where his reasoning is wrong?
Find the exact difference between the largest ball and the smallest ball on the Hepta Tree and then use this to work out the MAGIC NUMBER!
Make an estimate of how many light fittings you can see. Was your estimate a good one? How can you decide?