1. Put two squares with a side length of 5 cm into a rectangle. The circumference of a rectangle is () cm and the area is () cm2.

2. If there is a number, the number around one million digits and the number to the left of one hundred digits are "8", and the other digits are "0", then this number is () digits, which is recorded as () and read as (). If this number is rounded to ten thousand digits, you will get ().

3. Draw angles of 90, 75, 15, 150 with a pair of triangles.

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What is the result of (1) four 12 divided by 576?

(2) What is the quotient of 6 divided by the sum of 96 and 256?

5. I forgot the bracket (□+ 15)×4 in careless calculation, and the final result is 90. Do you know the correct answer?

6. Uncle Wang's family is going to lay floor tiles in a room 9 meters long and 5 meters wide, and each square meter needs 16 floor tiles. How many floor tiles does Uncle Wang want to buy?

7. Use three weights, 1 g, 4 g and 9 g, and do not put the weights and objects on the same plate. How many kinds of objects with different weights can a balance weigh?

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