How many digits are in the number (8^15)*(5^37) no calculator.

The radius of the earth is 3960 miles. What length of string would you need to wrap it around the earth at the equator?

Imagine you hang the string on a pole 6 feet high. How much more string would you need to encircle the earth at the equator?

Suppose you have a square with its perimeter equal in length to the circumfrence of the earth. If you draw a new larger square, whose sides are 6 feet away from the inner square. Would the perimeter of the new square be greater than, less than or equal to the total amount of string need to encircle the earth 6 feet above the equator as in the previous question?

Suppose you had nine eggs with one containing a jewel in the center and hence heavier. Given two balance scales of which you can make one measurement on each, how would you determine wich egg contained the jewel.


A square cake measures 15 inches by 15 inches by 3 inches tall and is frosted on the sides and on the top. How could you cut the cake into 5 pieces so that each piece has exactly the same amount of cake and frosting.?

A damsal in distress is stuck in a tower in a square castle surrounded by a square moat. The moat is 20ft across. The night has two planks 19ft long by 8 inches wide but no nails, screws, saws or superglue. Is it possible to rescue the damsal in distress.

Two rooms are connected by a hallway that has a bend in it so that it is impossible to see one room while standing in the other. One room has three light switches. Exactly one of the light switches turns on the light in the other room and the remaing two switches are not connected to any lights. What is the fewest number of times you would walk into the other room to figure out which switch turns on the light and how? (no guessing)

This was the beginning of a 1 cedit class that will be focusing on calc practice. It is supposed to be a fun way to hone your calc skills. None of these brain teasers require calc but if people are interested and we continue to do interesting problems like this in the future I will post each week.