1B. Find the sum of the following nine products: 1 × (10 – 1), 2 × (10 – 2), 3 × (10 – 3), … , 9 × (10 – 9). 1C. A square tablecloth covers an area of 256 sq. in. It is folded in half some number of times until the area that it covers is 8 sq. in. How many times was it folded in half?

1D. In a warehouse, a group of identical robots fills orders. In 10 minutes, 5 robots can fill 20 orders. If 8 robots worked at that same rate for an hour, how many orders would they fill?

1E. The number 2A5A0A2 is divisible by 99. What is the digit A?