Working systematically

Only one side of a two-slice toaster is working. What is the quickest way to toast both sides of three slices of bread?

My briefcase has a three-number combination lock, but I have forgotten the combination. I remember that there's a 3, a 5 and an 8. How many possible combinations are there to try?

Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.

Exactly 195 digits have been used to number the pages in a book. How many pages does the book have?

On a farm there were some hens and sheep. Altogether there were 8 heads and 22 feet. How many hens were there?

In a league of 5 football teams which play in a round robin tournament show that it is possible for all five teams to be league leaders.

In how many distinct ways can six islands be joined by bridges so that each island can be reached from every other island...

Your partner chooses two beads and places them side by side behind a screen. What is the minimum number of guesses you would need to be sure of guessing the two beads and their positions?

Can you use this information to work out Charlie's house number?

All CD Heaven stores were given the same number of a popular CD to sell for £24. In their two week sale each store reduces the price of the CD by 25% ... How many CDs did the store sell at each price?