So I have been working on a math / puzzle book for kids on and off for a number of years. It is taking forever, as I find it quite hard to come up with new problems. In an attempt to speed things up I decided to collect examples of common problems, and problems I either liked or disliked, here so I could talk about them with friends.

• Two cuts giving seven pieces; make two cuts to an object and be able to make seven equal value payments.

• Square in a circle in a square
• Graphical proof of the phthagorean theorem
• Chop up an "L" shape into equal pieces
• Tile a square with five rectangles

• "Up Down" problem
• Painting rate problem Simple rate example.
• Grazing rate problem
• Bridge crossing with a bicycle
• Find the jar, of a set of five jars, that contains contaminated pills
• "A consistent sum"
• Using a scale and 4 weights measure an integer load ranging from one to 40

• Twins lier problem
• Locked room with a light bulb problem
• 15 constrain "Einstein" problem

• Prohibited connection
• Pouring problems, using two different sized containers generate an accurate measurement of a third quantity.
• With a scale find the lighter fake in a group of items

Problems that are not really puzzles, but I thought had an important enough aspect to them that I should try and fit them into the book.

• Prove the quadratic equation

Just an area for notes / misc material on problem solving.

• Impossible game of catch
• What direction can you throw a ball so it always comes back to you?