#1: Place the numbers 1 through 10 (each used exactly once) into the circles so that each pair of consecutive circles is farther way than the last pair.
#2: In a certain country, it takes a minimum of 5 coins to make 13 centos, and a minimum of 4 coins to make 14 centos. What are the denominations of the coins in this country?
#3: Assign the values 1 to 10 to the weights in the diagram so that everything balances as shown. Each number will be used exactly once.
#4: Place the numbers from 1 to 9 in the blanks to make the equation correct. Each digit will be used exactly once. Operations are to be performed strictly from left to right. All intermediate results are positive whole numbers.
__ – __ / __ + __ / __ + __ / __ x __ – __ = 72
#5: Enter a different digit from 1 to 9 into each of the boxes so that each of the four equations reading across is true. All calculations are done from left to right and involve only positive integers.
#6: Assign the values 1 to 12 to the weights in the diagram so that everything balances as shown. Each value will be used exactly once.
#7: Find a looped path through the grid subject to the following constraints: the path must proceed from one cell to an adjacent cell, it must pass through no cell more than once, it must not go through any numbered cells, and must never make a sharp 60o turn. Each number indicates how many of the adjacent cells are part of the path.