Children's House of -Math

Growing Old is Mandatory.... But ... Growing up is Optional!

Mind Teasers

If You Are 11-14 years old ; and You Love Mind/ Math teasers ... This Page is for you! This page is divided into 2 sections:

Mind Teasers I

11&12 years old

1. Marcia has a small greenhouse with 100 plants. She gives each of her plants 300 milliliters of water twice a week. How many liters does it take to water all her plants for a year?

2. During the 20-game season, squeaky McLaughtin shoots an average of 14 regular baskets and 5 foul shots per game. He gets 2 points per basket and 1 point for each foul shot. How many points does Squeaky usually score in a game?

3. The Garcia family drinks a carton of citrus Sparkle a week. A carton of 8 one-litter bottles cost $2.79. If Mr. Garcia buys 120 bottles, how much does he spend?

4. In the Starlight Theater, rows 15 through 33 are reserved for birthday groups. There are 6 seats in each row. How many people can sit in the birthday section? (Hint: watch out when you are counting the number of rows !!!)

5. Last summer Terry worked on a tomato farm. His employer agreed to pay him 1 cent for the first plant he picked, 2 cents for the second, 4 cents for the third, 8 cents for the fourth and so on until he had picked all 12 bushes. How much he get paid in total for the 12 bushes.

6. Karla works Monday through Thursday from 9:00 AM to 5:00 PM, and Friday and Saturday she works from 4:00 PM to 10 PM. On Sunday she works from 1:00 PM to 6:00 PM. How many hours does she works in a week.

7. Ray is mixing punch for the Thanksgiving dinner. How many liters of punch does he need in order to give each of the 48 guests 200-ml servings?

8. Josephine buys perfume when it is on sale. Which is the better buy, How much she will save buy buying the cheaper one?

Sweet Paradise: 300 ml for $7.50 or

Simply heavenly: 400 ml for $9.48

9. "Hamburger Heaven" sold 750 hamburger, 510 hotdogs, 976 pieces of apple pie, and 1545 drinks last month. If the average price of each item is $0.65, how much money did "Hamburger Heaven" take in last month?

10. Miguel was counting the lights on the parade floats. Each float was 8 m long, and the floats ran bumper to bumper for 1 km. If there were 150 lights on each float. How many lights did he see?

11. The art teacher told the students to create new animal pictures by putting 2 animals together. They could use the giraffe, Elephant, Monkey, Ostrich, Lion and Camel. How many different animals could they create?

12. In a county fair pie-eating contest, Joe ate three pies in 20 minutes. At the same speed, how long did it take him to win the contest by eating 21 pies?

13. Ignoring the rules of logical math, if one-quarter of 100 was 30, what would be one-half of 300 be?

Mind Teasers II

12&13 years old

14. Mindy, Ned, Opal and Paul were skipping rocks in a lake. Paul's rock skipped 8 more times than Mindy's. Mindy's skipped 3 more times than Ned's. Ned's rock skipped 1/2 as many times as Opal's. Opal's rock skipped 8 times. How many times did Paul's rock skip? (Hint: Using the given facts, start with Opal's number and work backward)

 15. Timmy, Jimmy, George and Ricardo went fishing. Each boy caught 1 fish. Timmy's fish was twice as long as Jamie's was. Jamie's fish was 9 cm. Shorter than George's. George's fish was 12 cm. longer than Ricardo's. Ricardo's fish was 18 cm. long. What is the total length of the 4 fishes?

16. Martin's exercise program requires that he do 1 push-up the first day, 4 push-ups the second, 7 push-ups the third, 10 the fourth day and so on until he does at least 30 push-ups each day. How many days does Martin need to reach his goal of 30 push-ups per day (Hint: look for a pattern)

17. A squirrel found 50 acorns in a 5-day period. Each day the squirrel found 3 more acorns more than the day before. How many acorns did it find each day?

18. A hot-air balloon covered 2,100 km in 7 days. If it covered 50 km more each day than the day before. How many km did it cover each day?

19. In a frog-hopping contest, Leaping Louie finished 1 leap ahead of Able Mable. Able Mable was not in last place. Muddy Buddy finished 7 leaps ahead of Hopping Henry. Hopping Henry finished 3 leaps behind Leaping Louie. Leaping Louie finished 5 leaps behind Dynamite Dixie. Who won the race?

20. Ms. Mazzeroni raises guppies. One day she found that 20 of her fish had died. She bought the same amount as were still living. She divided the fish equally and sold them to 6 customers. Each customer bought 15. How many fish did she have to start with?

21. Mr. Kim just got a new job selling car insurance. The first month he had 2 new customers. The second month he had 8 new customers. The third month he had 32 new customers. If this pattern continues, how many new customers will Mr. Kim have in the sixth month?

22. Gloria has twice as many brothers as sisters. Her brother Paul has the same numbers of sisters as brothers, how many girls and boys are in the family (sisters and brothers)

23. What is the number that is double one-tenth of one-fourth of one-third of one-half of 2400?

24. Charlie was only four, but he liked several girls in his nursery school class. He gave them gifts as follows: To the first, he gave her half the candy hearts he had, plus one; to the second, he gave her half of what he had left, plus one; to the third, he gave her all he had left (that was only one). How many candy hearts did he start out with?

Mind Teasers III

13&14 years old

25. It was the day of the big furniture sale, "oh" said Pat, "this chair was $350, reduced by 20%, then by $80, then by 80%. I wonder how much is it by now??"

26.The floor of a rectangular room is covered with square tiles. The room is 10 tiles long and 5 tiles wide. Find the number of tiles that touch the walls of the room

27. Five students named Fred, Gail, Henry, Iggy and John are seated around a circular table in that order. To decide who goes first in a game, they play "countdown". Henry starts by saying "34", with Iggy saying "33". If they continue to count down in their circular order, who will eventually say "1".

28. which of the following numbers is an odd integer, contains the digit 5, is divisible by 3 and lies between 12 square and 13 square.

29. In a "fibonacci" sequence of numbers, each term begining with the third, is the sum of the previous two terms. The first number in such a sequence is 2 and the third is 9. What is the eigth term in the sequence?

30 In a softball league, after each team has played every other team 4times, the total accumulated points are: lions 22, Tigers 19, Mounties 14, and Royals 12. Each team received 3 points for a win, 1 point for a tie and no points for a loss. How many games ended in a tie?

31 If the sales tax rate were to increase from 7% to 7.5%, then the tax on a $1250 item would go up by how much?

32 In a set of five numbers, the average of two of the numbers is 12 and the average of the other three numbers is 7. What is the average of all five numbers

33 In a traffic study, a survey of 50 moving cars is done and it is found that 20% of these contain more than one person. Of the cars containing only one person, 60% of these are driven by women. Of the cars containing just one person, how many were driven by men?

Other topics you will find in the "cool Math":