In a survey of students, 2/3 of the girls and 3/4 of the boys preferred using pens over pencils.
Girls make up 60% of the students in the school.
What percent of the students prefer using pens?
A bag contains six green, five gray, and four violet disks.
If a disk is drawn at random from the bag, what is the probability that the disk drawn is green?
There are 16 pieces in a bag.
If you take one piece out of the bag without looking, which piece are you most likely to draw?
Mark tosses a dime three times in a row.
The tree diagram shows all possible outcomes.
What is the probability that Mark will toss two or more heads?
The US Census Bureau stated that 6,830,000,000 people lived in an area of 125,640,000 sq. km in 2010, or about 54 people per sq. km.
The population will be 9,200,000,000 in 2050.
How many people will live per square kilometer?
On the chessboard, what is the probability that a randomly chosen square is dark and does not touch the outer edge of the board?
The faces of a cube are numbered from 1 to 6.
I roll the cube once.
Which outcome is least likely to occur?
Anna recorded the temperature every day for a week (7 days).
It was 22°C on Monday.
The temperature decreased by 2°C every day.
What was the average temperature for the week?
The sum of 19 consecutive integer numbers is 2090.
What is the difference between the largest and the smallest of these numbers?
Which scatter plot best shows the relationship between a person's height and the time that person spends playing computer games?
The table shows the results of a competition among 5 teams.
How many teams received more points than the average?
Each of four children chose one of these cards.
They multiplied the chosen numbers.
Which number cannot be the product of those numbers?
Fifty-two percent of the households in Funnytown have children and twenty-five percent have pets.
What percent has both?
I place 5 dominos face up on my table.
I have to get all the dominos facing down by flipping over three dominos in each move.
What is the minimum number of moves?
On average there are 100,000 strands of hair on a person's head.
Hair grows at a rate of about 15cm a year and each hair lasts up to 6 years before it falls out.
If the population of London is 8,000,000, what is the probability that at least 2 of the inhabitants have the same number of hairs on their heads, discounting bald people?
A school store's expenses and sales for a three-day period are shown in the table.
In which week was the store's profit a maximum?
There are 16 pieces in a bag.
You are going to take one piece out of the bag without looking.
Which shape would you be most likely to draw?
Tim received the following scores in the online math tests:
80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, and 90%
What was his average (mean) score?
A week ago, Anna's jar was filled with 120 jellybeans.
She always took the jellybeans without looking into the jar.
Today, there are 11 green and 9 red.
Estimate the number of red jellybeans she has eaten.
One person is chosen at random from the list.
What is the probability that his/her name contains the letter "a"?
Bobby writes each letter of his name on a separate card.
He randomly chooses one card.
What is the probability that the card is not an "B"?
Fifty percent of Funnytown's households have children and 20% have pets.
If 10% have both, what percent have neither?
A palindrome is a number whose value is equal in either direction.
For example, 12321 is a five-digit palindrome.
How many five-digit palindromes exist?
A bus carrying 5 tourists travels to Dogland. Every tourist has a dog. Every dog has 5 puppies. A dog has 5 toes on each paw.
How many toes are there in the tourist bus?
The United States has currency notes in denominations of 1, 2 and 5.
How many ways are there to form exactly $10 using multiples of only these bills?
Two friends and I have gone out to dinner. The bill comes to $150.00. Everybody agrees to tip $10.
What tip would we leave our server?
The photograph courtesy of Roland Sauter
Alex and Bill both have some money.
Alex is short of two dollars and Bill of three dollars to buy a bird.
If they pool their money, they are still short of money.
How much does the bird cost?
Alex likes 81 but not 82; he likes 49 but not 50, he likes 225 but not 224.
Which of the numbers below does he like?
The diagram shows my Saturday morning activities.
If I rearrange the schedule, but never do more than two activities at once, what is the shortest amount of time I can take?
The diagram shows a road network.
All cars drive in one direction from A to B.
The numbers represent the maximum flow rate in vehicles per hour.
What is the maximum number of cars that can drive through the network every hour?
There are two ways to add four odd numbers to get 8:
5 + 1 + 1 + 1 = 8
3 + 3 + 1 + 1 = 8
Changes in the order of numbers do not count as new solutions.
How many ways can you add four odd numbers to get 12?
Carl Friedrich Gauss (1777-1855) is one of the world's most famous mathematicians.
When Gauss was about 9 years old, to make students busy for a long period of time, his teacher asked students to add the integers from 1 to 100.
While his classmates toiled away doing the addition longhand, Gauss immediately wrote the correct answer.
Can you do the same?
Gerry sent three letters to three girlfriends.
The postman put the letters into three different boxes without looking at the name of the recipient.
What is the probability that all girls received their letters?
How much does a sales representative earn from the sale of seven $50,000 cars if he receives a 2% commission?
Find the sum of all the numbers in the pyramid if each number is the sum of the four numbers directly below it.
If I lose 25% on an investment during the first year and gain 20% the following year, what is my net loss?
There were 4,492,205 articles and 21,140,000 contributors in the English version of Wikipedia on Monday 14 April 2014.
What is the average number of contributors per article ?
According to a study, hair grows about half a millimeter each day.
How much time does it take for Evguenia's hair to grow 1 meter (1000 millimeters) longer?
The sum of Jim, John and Jane's ages is 27.
If the twin brothers are older than 7 and younger than their sister, how old is Jim?
(All ages are whole numbers.)
I decided to save a dollar in January, then increase the amount by one dollar each month.
How much will I save in a year?
John has an average of 60 marks on his first Math tests.
He missed the last (fifth) test and got zero.
What is the average score now?
The question is typical for PISA Test.
PISA stands for Programme for International Student Assessment.
A sundial (shadow clock) is a device that tells the time of day by the position of the Sun.
Find the sum on the sundial numbers.
There are 5 children in a boat.
Four of them do one of the activities below.
What is the fifth kid doing?
Once upon a time, there were three little pigs.
If two brothers weighed 45kg, what is the most probable weight of the third brother?
A waiter receives 15% tips from each table in a restaurant.
What is the minimum order that allows him to reach his target of a $5 tip per table?
Gerry puts 1/10 of his $50 weekly allowance in the bank for college.
How much does he save in a year if he gets the money every week including holidays?
Gerry tries to play tennis but can only hit the ball 40% of the time.
If 80 balls are hit to Gerry, how many balls can you expect him to hit?
Jane has forgotten the address of her friend’s house, but knows it contains the number 1.
She wants to choose one of the directions, and then recognize the house, which she visited a couple of years ago.
Which direction has more mathematical chances?
How many different ways are there to go from the top to the bottom going along and in the direction of the arrows?
The Eiffel Tower is a wrought iron lattice 320-meter-high tower in Paris, France.
The Eiffel Tower is the most-visited paid monument in the world; 6.91 million people ascended it in 2015.
Estimate the average number of visitors per day.
A thumb war tournament had eleven players. Each player played every other player only once, with no ties.
If ten players each won half of their games, how many games did the eleventh player win?
The 4 × 400 metres relay is an athletics track event in which teams consist of four runners who each complete 400 metres or one lap. Relay race runners typically carry a relay baton which they must transfer between teammates.
Anna runs a complete lap in 1 minute, 8 seconds; Betty in 1 minute, 16 seconds; Cindy in 1 minute, 11 seconds; and Dianna in 59 seconds.
What is the final result of the team?
For the Easter Egg Hunt, 18 students hunt for 112 hidden eggs.
7/9 of the children have found 3/4 of the eggs, the remaining eggs being undiscovered.
What is the average number of eggs found by each lucky child who discovers at least one egg?
How many different ways from A to B are there, given that you can only move along the arrows, and only in the same direction as the arrows?
Elephants eat roughly 10 percent of their bodyweight in food every day.
If the family ate 720 kg (nearly 1600 lbs) of food yesterday, estimate the total weight of the family.
1 ton = 1000 kg
I choose two rules:
If the number is even, divide it by two.
If the number is odd, triple it and subtract one.
If I start with 3 what is the 100th number?
A large sheet of print paper is 0.1mm thick. Gerry cuts it in half and places one piece on the other to make a pile. These are cut in half and all four pieces are placed in a pile, and the process is continued.
Estimate the height of the pile after the tenth cut.
1cm = 10mm
Gerry and his brother shoveled the pathway to a cottage. It took the two of them an hour and half to complete the job together.
However, because Gerry is stronger, he shoveled twice as much of the driveway as his brother.
If his brother had worked alone and maintained his same pace, how much time would it have taken him to do the entire job by himself?
You can put 20 crosses on a 5x5 board without making five-in-a-line in any direction.
What is the largest number of crosses you can place on a 55 x 55 board without making fifty-five-in-a-line in any direction (left-right, up-down, or diagonal)?
Koalas rarely drink water because they eat mostly the leaves of Eucalyptus which contain 55% water already.
When Kool the Koala is not sleeping, he eats 75 grams of leaves per hour.
If Kool sleeps 20 hours every day, how much water does he consume per day?
1 million = 1,000,000
Million . . . 6 zeros
Billion . . . 9 zeros
Trillion . . . 12 zeros
Quadrillion . . . 15 zeros
Quintillion . . . 18 zeros
Vigintillion . . . 63 zeros
Googol . . . 100 zeros
How many zeros are there in two billion of three trillion?