40 Brain Games Guaranteed to Boost Your Brain Power
Your brain isn’t a muscle—in fact, it’s mostly fat!—but the right kind of mental exercise can help keep it in shape. These puzzles are designed to give your problem-solving, reasoning, and concentration skills a workout. And they come in varying degrees of difficulty, so pace yourself!
How many times does the digit 5 occur in the numbers from 1 to 100?
Twenty times. The digit 5 appears ten times as a last digit (5, 15, 25 … 95) and ten times as a first digit (50, 51, 52 … 59). Check out these word puzzles that will leave you stumped.
The grid contains matches of different sizes, any of which may be completely unburned, partially burned, or completely burned. Matches burn from the head (the red end) to the tail without skipping segments. The numbers outside the grid indicate the number of burned segments in the corresponding row or column. Can you shade in the burned segments to “match” the numbers?
Try these morning brain boosters to keep your mind sharp.
Sophie and Caroline made arrangements to meet at a café at 2 p.m. Sophie thinks her watch is 25 minutes fast, although it is actually 10 minutes slow. Caroline thinks her watch is 10 minutes slow, while it is actually 5 minutes fast. What will happen if they both aim to arrive exactly on time?
Sophie will be 35 minutes late. Caroline will arrive at 1:45 p.m., 15 minutes ahead of time. See if you can solve these really tricky brain teasers.
Meteor Showers Bring Spring Flowers
Space dust has landed on Earth, carrying with it seeds for exotic new alien flowers. One of them still lacks a name. If the xenobotanists follow the same rules they used to create the other terms, what should they call the last flower?
Cosmofilium jupibristo. The first half of the top term tells the color of the flower’s center; the last half is the petal color. The first half of the bottom term tells the shape of the flower’s center; the last half is the shape of the petals.
Place the words listed below in the crossword grid.
Only the smartest people can solve these detective riddles.
The Long and Short of It
Marcel Danesi; illustration: iStock
Six neighborhood children— Leisha, Benito, Delia, Charlotte, Weldon, and Zina—were measured yesterday. Weldon is taller than Delia but shorter than Zina. Leisha is taller than Benito but shorter than Delia and Weldon. Benito is not the shortest. List the kids in order of height from tallest to shortest.
Zina, Weldon, Delia, Leisha, Benito, Charlotte.
A whole number between one and seven belongs in each of the seven bubbles. Each number occurs once. The sums of some of the numbers are revealed in the areas where their bubbles overlap. Can you figure out which number goes in each bubble?
Test your numbers knowledge with these math riddles.
None of the white squares in this diagram have their edges lined up. One of the squares is a different size from the others. Can you find it?
These are the toughest riddles ever. Can you solve them?
Carmela receives a text message from an unfamiliar number, so she texts back, “Who is this?”
The strange response: “It’s one of your female relatives. Your mother’s mother is my father’s mother-in-law.” Even assuming that this information is true, it doesn’t help Carmela pinpoint an individual, since there are two relationships it could describe. What are they?
Sister or first cousin.
Complete the grid so that each row, each column, and each three-by-three frame contains the nine letters from the black box at the top. The hidden nine-letter word is in the diagonal from top left to bottom right.
Only 2 percent of people can solve Einstein’s Riddle. See if you can beat it!
More or Less
Place the hexagons below into the pyramid so each number is either greater than the sum of the two numbers below it or less than the difference between them. For instance, if two adjacent numbers were 20 and 50, any number higher than 70 or lower than 30 could be on top of them. (And no, do not turn 98 upside down to make it 86!)
If you can solve the secret word in this logic puzzle you might be a genius.
Kate and Faizal both believe that they need a cup of coffee every three hours to stay awake and function. They both drink their first cup at 8 a.m. and another one every three hours thereafter until they go to sleep. Considering the following facts, who is spending more on coffee each week?
- Kate stays up until 10 p.m. Sunday through Thursday and until midnight on Friday and Saturday. Faizal stays up until 10 p.m. every day.
- Kate pays $3 per cup of coffee. Faizal drinks higher-grade organic coffee and pays $4 per cup.
Faizal. He spends $140 per week, while Kate spends $111. See if you can find the doll hidden in this picture.
You just bought nine beautiful lakeside campsites, which you can rent to campers with tents for $20 per campsite per night. You can also upgrade the sites with electrical hookups. This will cost you $60 per campsite but will allow you to rent to RVers for $40 per night. Suppose you can always fill your campground to capacity. If you’re starting without any cash on hand, how many nights will pass before you’ll be able to upgrade all nine sites?
Three. On the first night, you’ll host nine tents and make $180, which you’ll use to upgrade three sites. On the second night, you’ll host three RVs and six tents, earning $240, letting you upgrade another four sites. On the third night, you’ll host seven RVs and two tents, earning you more than enough to upgrade the last two.
Place one of the four basic arithmetic operations (+, –, ×, ÷) in each box to make a correct equation. All operations are performed from left to right, ignoring the mathematical order of operations. The result at each step must be a positive whole number. What’s the equation?
5 + 7 ÷ 3 × 9 – 4 = 32
The playing card suits in the cells above are placed according to a pattern. What’s the missing symbol?
Spade. Each suit has a numerical value: diamonds equal one, hearts equal two, spades equal three, and clubs equal four. Or, if you prefer, diamonds equal four, hearts equal three, spades equal two, and clubs equal one. Either way, each row and column adds up to ten, and the missing symbol is a spade. Now, can you guess which flag comes next in this puzzle?
How many pets live in my house if all of them are snakes except two, all are hamsters except two, and all are rabbits except two?
One of each, for a total of three.
Win or Lose
The Reds, the Grays, the Blues, and the Blacks have a round-robin tournament wherein each team plays each other team once, for a total of six games. The Blacks won more games than the Blues, and the Grays lost more games than the Blues. The Reds tied the Blacks, the only tie in the tournament (a tie counts as neither a win nor a loss). Who won the game of the Reds versus the Blues?
The Reds. The Blacks tied one game, so they won a maximum of two games. They won more than the Blues, so the Blues won a maximum of one game. Since the Grays lost more times than the Blues, the Grays must have lost all three matches. The match that the Blues won must have been against the Grays, so the Blues lost the match against the Reds. Can you find the missing number in this puzzle?
Place the words listed below in the crossword grid.
See if you can spot the difference between these nearly identical animals.
Lois and Helen, widowed sisters, lived together out in the country. Their habits never changed: up at dawn, breakfast, some housework and gardening until lunch. In the afternoon, Helen napped while Lois watched her shows—Helen never watched TV. Then Helen would clean the vegetables for dinner and Lois would cook. In the evening, they’d read before bed. One night before they turned in, a storm knocked out the power. Everything was pitch-black, and Lois began to panic. “What should we do?” she cried. Helen just smiled and kept reading. Why did Helen stay calm while her sister did not?
Helen was blind.
Jake loves steak; Trish loves fish
Jacob enjoys steak so much that the probability that he’ll have it for dinner on any given evening is one in three. The favorite dish of his wife, Patricia, is fresh fish. The probability that she’ll have it for dinner on any given evening is one in two. Because Jacob and Patricia always dine together, they’ll never have steak and fish on the same night. On average, how many times in a 30-day month will they be having either steak or fish?
25 nights. Over 250,000 people have tried to solve this riddle—can you?
Each of the three lines of letters below spells the name of a fruit, but four letters from the first word are in the third line, four letters from the third word are in the second line, and four letters from the second word are in the first line. What are the words?
Tamara has $20,000 saved up. If four-fifths of what Tamara has equals eight-ninths of what Martina has, how much money does Martina have?
Each letter from A through H has one of the eight values listed below, and no two letters have the same value. Which number goes with which letter to make all the equations true?
A = 6, b = 13, c = 1, d = 7, e = 16, f = 3, g = 5, h = 10
Jerry Mander Strikes Again
Roderick Kimball of Enigami Fun
Your name is Jerry Mander, and you must draw your town’s voting districts so that George Greene becomes dogcatcher rather than Barbara Blue. To do that, Greene must win the majority of the city’s five voting districts. Each district comprises three households. This map shows how each of the town’s 15 households will vote (the tree represents a park that’s not in any district). The catch: The three households in each district must share at least one border with at least one other household in the district. Can you draw the five districts in a way that guarantees Greene defeats Blue?
Roderick Kimball of Enigami Fun
Next, try your hand at some of the most famous riddles in history.
Place one of the four arithmetic operations (+, –, ×, ÷) in each box to make a correct equation. All operations are performed from left to right, ignoring the mathematical order of operations. The result at each step must be a positive whole number.
25 + 24 − 1 ÷ 8 = 6
Have a Chocolate
Dad: “Where are the chocolate bars I bought?”
Daughter: “I gave half of them to Mom and half of a bar to my little brother. Then I gave half of what was left to Grandma and half of a bar to my little sister. That left me with one bar, which I gladly ate myself.”
How many bars did Dad originally buy?
There Goes the Neighborhood
Roderick Kimball of Enigami Fun
Each of the six people quoted below lives in one of the six houses in the neighborhood shown. The houses are white, brown, green, blue, yellow, and orange. Assuming that everyone is telling the truth, whose house is painted which color?
Mrs. Antonini: Mrs. Borden lives due north of me.
Mrs. Borden: I live in the orange house. I can walk to Mrs. Englehardt’s house without crossing any streets.
Mr. Cruz: I live due east of a green house.
Miss Dubois: There’s a white house north of mine, but I can’t see it from my house, because there’s a brown house in the way.
Mrs. Englehardt: I live directly across a street from both a yellow house and a white house.
Mr. Fung: I live in the green house.
Erik bought some identical brass buttons for a jacket, each for the same price. It just so happens that if you add two to the number of buttons he bought, you get the price of each button in cents. If he spent a total of $4.83, how many buttons did he buy?
21 buttons (For 23 cent each).
You need to acquire at least six pencils, six pens, and six erasers for $5.20 or less. If the packages listed below are the only combinations that are available, which do you take? You can buy more than one of the same package.
A. Two erasers for 70 cents
B. Four pencils, one pen, and two erasers for $1.30
C. Three pencils, four pens, and three erasers for $3.20
D. One pencil, three pens, and two erasers for $1.90
E. One pencil and five pens for $2.30
Buy one B and two D’s for $5.10.
Using all the letters listed below only once, can you find the names of three spices?
Cardamom. Cinnamon. Nutmeg.
Insert the letters A to K, one per square, so that no two letters in consecutive alphabetical order touch, not even at a corner. Five letters have been placed to get you started.
Can you pass the world’s shortest IQ test? It’s really hard, less than 20 percent of people can.
You need to empty the contents of two of the five boxes listed below into a bag. Which two will give you the best chance of drawing a red ball at random from the bag?
Box A: 3 red balls, 5 silver balls
Box B: 4 red, 6 silver
Box C: 7 red, 9 silver
Box D: 1 red
Box E: 12 red, 14 silver
Boxes D and E, which give you a probability of 13/27 (48 percent) of getting a red ball.
Francesca is as old as the combined ages of her brothers, Harry and Ernie. Harry is two years younger than Ernie. When everyone was a year younger, the combined ages of the three siblings was three quarters of the sum of their present ages. How old is each sibling now?
Francesca is six, Harry is two, and Ernie is four.
Replace one letter from each of these words to form a common two-word phrase.
Replace the B in the first word with an R and the S in the second word with an H for rush hour.
Place these commonly misspelled words in the crossword grid.
There are eight semiprecious gems in Ellen’s collection. At current market prices, four are worth $5, three are worth $10, and one is worth $25. She gives them to her three children: Matthew, Aaron, and Jeremy.
The total value of each child’s gift
is the same.
Jeremy receives exactly three stones.
Matthew receives the lowest number of stones.
How are the gems distributed?
Matthew: one stone worth $25
Aaron: one stone worth $10 and three worth $5
Jeremy: two stones worth $10 and one worth $5
Under the same flag
On the top are the names of five boats that belong to the same company. Which one of the five names on the bottom would fit in with the rest?
The top names contain a Roman numeral and a number that matches its value, so NAXIR 11 fits in with them.
What am I?
I run but never walk. I gurgle but don’t talk. I have a bed but never sleep. And I have a mouth but never eat. What am I?
Party at Charlie’s
You’ve been invited to a party at Charlie’s house. As part of the fun, you’ve agreed to solve a puzzle to figure out where he lives. He has seven friends who live nearby. They’ve given you a map showing all of their houses and Charlie’s house, along with the following information:
Daniel: I can’t see Benita’s house,
because Greta’s house is in the way.
Adam: I live directly (not diagonally) across the street from Daniel.
Benita: Elena lives due west of me.
Elena: I have to cross three streets to walk to Franco’s house.
Hal: I live east of Benita.
Where does Charlie live?
Great minds love games
Doing a crossword or a Sudoku every day to keep your mind sharp may seem like a recent concept. In fact, people have been challenging their brains with puzzles as far back as 3,600 years ago, when the ancient Egyptians developed math problems on papyrus and wooden tablets. Want more puzzles? Our Mind Stretchers books are available online and wherever books are sold.