Logic Puzzles
Logic puzzles are riddles or situations which require some effort to figure it out. Some require gathering all the clues to figure out what the answer is, some involve looking at the problem in a new light, some require thinking outside the box, and some require good ol' fashioned trial and error!
Simple Logics (or; Math Puzzles)
Simple logic puzzles often are accompanied by a picture; you're given a situation and you have to figure out the desired outcome. One example of these is the river crossing puzzle; where you are given a group of people/objects and have to figure out how to get them to the other side within a set of rules. For example, in the above picture, the two children cannot be left alone on the island, and the dog cannot paddle the boat by itself. Another type of simple logic puzzles are math problems, like Bridges (also known as Hashi) or Numberlinks. You have to figure out the best path to connect two numbers/objects, but you can't cross over other paths, you can only go up/down or left/right, and you need a certain number of paths from each spot based on the number (ex. If there is a 5 on the spot/island, it needs 5 bridges connecting it to other spot/islands). One of my favorite types of simple logic puzzles are riddles; ones that require you to think outside of the box. "Imagine you are in a room; no doors, no windows, nothing but walls, floor and ceiling. How do you get out?" Answer: Stop imagining the room!
Where to practice:
How to solve: The best way to start out with these ultimately is trial and error. For river crossings, write out how long it would take for the fastest and slowest person to go across, and keep adjusting for who is next based on the rules you're given. For bridges/numberlinks, start with the ones that can only connect to one other number. After that, the ones in the corners. Next, do the island/number with the most connecting bridges, then the least. Keep adjusting where your lines are as you need to. For riddles, the best thing to do is first look at the wording. Is there any word that has more than one meaning that could change the answer? Then try to think of it as if you were telling it to a child. Based on a limited world knowledge, what would you say the answer is?
How to make: As with most puzzles, the best thing to do is first draw the solution. Then erase the parts that are the answer. Then try to solve it again, making sure you there is only one solution. Remember, it is best to have a friend try to solve it too!
Where to practice:
How to solve: The best way to start out with these ultimately is trial and error. For river crossings, write out how long it would take for the fastest and slowest person to go across, and keep adjusting for who is next based on the rules you're given. For bridges/numberlinks, start with the ones that can only connect to one other number. After that, the ones in the corners. Next, do the island/number with the most connecting bridges, then the least. Keep adjusting where your lines are as you need to. For riddles, the best thing to do is first look at the wording. Is there any word that has more than one meaning that could change the answer? Then try to think of it as if you were telling it to a child. Based on a limited world knowledge, what would you say the answer is?
How to make: As with most puzzles, the best thing to do is first draw the solution. Then erase the parts that are the answer. Then try to solve it again, making sure you there is only one solution. Remember, it is best to have a friend try to solve it too!
Logic Grid Puzzles
Logic Puzzles with grids are the most-known type of logic puzzles. These puzzles are pretty straight forward; using the clues, figure out who did what/where/when/etc. The hardest part of these puzzles often comes with the wording of the clues. The easiest puzzles will tell you all of the components and have straightforward clues like "either Sarah or Tom hates sardines on pizza." The hardest will give you all the info you need to solve the puzzle, but you'll have to do some inferring, like when they say "Sarah had half as many slices of pizza as Fred, who had the second most slices of the three people. There are 12 slices total." Here the only number given to you is 12, but you know there are 3 people, and if Fred had the second most, Sara had the least, and the third person, who we know from a previous clue is Tom, had the most. So with some math trials, you know Sarah had 1 or 2, Fred had 2 or 4, and Tom had 6 or 9. (if Sarah had 1, Fred had 2, Tom would have to have 9; if Sara had 2, Fred had 4, Tom had 6. If Sarah had 3, Fred had 6, that would leave Tom with 4 which does not fit the part of the third person having the most. You would then use another clue to find out if Sara had 1 or 2). An important thing to remember is if you get a sentence with a condition, its either all true or all false. For example, "
How to solve: Lay out your grid. you can make one yourself, or find an empty grid online (like here). The grid shows you all the possible options in every category. places an "X" where a row and column meet means those items do not go to together, and placing a "O" means those items DO go together. Every option can only be used once in a puzzle, so when you place an "O" in a space, make sure the rest of the row and column in that category box is crossed off.
Scan through the given information and clues for all the values (names, dates, etc.). Then go through the clues. First start with the short, definite clues, like "Sarah did not have pepperoni pizza." Find the spot on the grid where "Sarah" meets "pepperoni pizza" and put an X. This means they do not go together.
Then go back through the other clues and make a note of the info you gained from that clue. When a row is full of X's except one space, you know that empty space is the correct item, so put a dot/circle/etc, and make sure you put an X in the rest of the column. In the previous clue, "Sarah had half as many slices of pizza as Fred, who had the second most slices of the three people. There are 12 slices total." your notes would be "Sara=1/2 Fred", "Fred=2nd most" "12 total". Then you would add what you inferred, "Tom=third guy" "Sarah =1 or 2" "Sarah =least amount of slices", "Fred=2 or 4" "Tom=6 or 9". Or if you have a clue that says "Of the two boys, one ate pepperoni and the other ate 4 slices" you know that 4 slices and pepperoni don't go together since they each have to belong to one of two boys.
As you are filling out the grid, make sure you are lining up across as well as up and down. For example, if you have Sarah had 2 slices of cheese pizza, make sure the part of the grid where "cheese pizza" and "2 slices" is also marked as the answer. This will help you later. After you are finished going through all the clues, go back through the ones you took notes on and see if you can solve them now. For instance, if later there was a clue that said "Everyone took an even number of slices" you would know that Sarah took 2, so Fred took 4, so Tom took 6. Finally, after you have gone through everything, double check your grid. Are there any rows/columns where all but one space has been marked off? Are there any that go together that would cancel out another selection? For example, if there were only 2 or 6 slices of cheese pizza, and cheese pizza is marked as going with Sarah who can only have 1 or 2, you know that cheese pizza can only have 2 slices since Sarah can't have 6.
If you're still having trouble, try asking a friend to go through the clues to see if there is anything you missed. If something lists the events happening during the week days, but the clues only give you Monday, Wednesday, and Friday, its pretty likely the last two days are Tuesday and Thursday. As a last resort; (if you can) check with the maker of the puzzle to make sure that what you have so far is correct and see if you were given all of the clues, and given the clues correctly. Sometimes homemade puzzles don't have all the info!
Where to practice:
How to make: I'm sure by now you know the drill! First step: make the grid with the solution filled in. Decide what the category for each box of rows/columns is first. Remember, the last column is the second row, the second to last column is the third row, etc. There should be no place on the grid where the same column/row meets itself. Second step: Make all of your clues based on the solution. It is important to mention all of the values in your clues or in the situation introduction, unless you are also providing the grid with the values pre-filled. If you don't directly say all the values, make sure you can infer them with your clues (this really only works for days of the week/months or numbers in a pattern). Third step: erase the grid marks that show the solution. Fourth step: with your clues, try to solve your puzzle, making sure there is only one possible solution, and that you gave sufficient clues to find all of the variables. Lastly, send it to a friend to doublecheck, making sure your clues aren't worded in a confusing way.
How to solve: Lay out your grid. you can make one yourself, or find an empty grid online (like here). The grid shows you all the possible options in every category. places an "X" where a row and column meet means those items do not go to together, and placing a "O" means those items DO go together. Every option can only be used once in a puzzle, so when you place an "O" in a space, make sure the rest of the row and column in that category box is crossed off.
Scan through the given information and clues for all the values (names, dates, etc.). Then go through the clues. First start with the short, definite clues, like "Sarah did not have pepperoni pizza." Find the spot on the grid where "Sarah" meets "pepperoni pizza" and put an X. This means they do not go together.
Then go back through the other clues and make a note of the info you gained from that clue. When a row is full of X's except one space, you know that empty space is the correct item, so put a dot/circle/etc, and make sure you put an X in the rest of the column. In the previous clue, "Sarah had half as many slices of pizza as Fred, who had the second most slices of the three people. There are 12 slices total." your notes would be "Sara=1/2 Fred", "Fred=2nd most" "12 total". Then you would add what you inferred, "Tom=third guy" "Sarah =1 or 2" "Sarah =least amount of slices", "Fred=2 or 4" "Tom=6 or 9". Or if you have a clue that says "Of the two boys, one ate pepperoni and the other ate 4 slices" you know that 4 slices and pepperoni don't go together since they each have to belong to one of two boys.
As you are filling out the grid, make sure you are lining up across as well as up and down. For example, if you have Sarah had 2 slices of cheese pizza, make sure the part of the grid where "cheese pizza" and "2 slices" is also marked as the answer. This will help you later. After you are finished going through all the clues, go back through the ones you took notes on and see if you can solve them now. For instance, if later there was a clue that said "Everyone took an even number of slices" you would know that Sarah took 2, so Fred took 4, so Tom took 6. Finally, after you have gone through everything, double check your grid. Are there any rows/columns where all but one space has been marked off? Are there any that go together that would cancel out another selection? For example, if there were only 2 or 6 slices of cheese pizza, and cheese pizza is marked as going with Sarah who can only have 1 or 2, you know that cheese pizza can only have 2 slices since Sarah can't have 6.
If you're still having trouble, try asking a friend to go through the clues to see if there is anything you missed. If something lists the events happening during the week days, but the clues only give you Monday, Wednesday, and Friday, its pretty likely the last two days are Tuesday and Thursday. As a last resort; (if you can) check with the maker of the puzzle to make sure that what you have so far is correct and see if you were given all of the clues, and given the clues correctly. Sometimes homemade puzzles don't have all the info!
Where to practice:
How to make: I'm sure by now you know the drill! First step: make the grid with the solution filled in. Decide what the category for each box of rows/columns is first. Remember, the last column is the second row, the second to last column is the third row, etc. There should be no place on the grid where the same column/row meets itself. Second step: Make all of your clues based on the solution. It is important to mention all of the values in your clues or in the situation introduction, unless you are also providing the grid with the values pre-filled. If you don't directly say all the values, make sure you can infer them with your clues (this really only works for days of the week/months or numbers in a pattern). Third step: erase the grid marks that show the solution. Fourth step: with your clues, try to solve your puzzle, making sure there is only one possible solution, and that you gave sufficient clues to find all of the variables. Lastly, send it to a friend to doublecheck, making sure your clues aren't worded in a confusing way.
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