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Maths starters
- 1. Maths Starters Insmall groups attempt to answer the following brainteaser questions.
- 2. Brainteaser question To celebratethe New Year, a principal orders 100 chocolate bars to give to her students. When the chocolate bars arrive, she realises the chocolate bars have a special offer. If you hand in 10 wrappers, you receive a free chocolate bar! If everyone in the school saves their wrappers, how many chocolate bars can the school get?
- 3. Brainteaser question What isthe largest number that can be a clue in Kakuro? (A Kakuro consists of a grid of boxes, some empty and some filled. Lines of empty boxes run across and down. These lines each have a clue – to the left of horizontal lines and above vertical ones. The aim is to write a digit from 1 to 9 in each empty box following two rules: 1.No two boxes in a line contain the same digit 2.Adding up all the digits in the line will equal the clue )
- 4. Brainteaser question Tasko theSea Lion lives at Adelaide Zoo. Recently, he was very sick, and the zoo’s vets realised he’d been eating some coins. They removed seven coins, adding up to $1.10, from Tasko’s belly. Since they removed the money, Tasko is feeling a lot better. Can you come up with a set of seven coins that add up to $1.10? How many ways are there to make $1.10 with seven coins?
- 5. Brainteaser question The daybefore yesterday, George was 12 years old. Next year, he’ll turn 15. How is this possible?
- 6. Brainteaser question Here arefour dots, arranged in a square: Without lifting your pen, draw three straight lines, pass through all four dots and finish up exactly where you started.
- 7. Brainteaser question Can youwork out the pattern in these numbers? 8, 5, 4, 9, 1, 7, 6, 10, 3, 2, 0
- 8. Brainteaser question • Oneday in class, the students were writing letters. Each student wrote one letter to each other student in the class. In total, 306 letters were written. How many students were there in the class?
- 9. Brainteaser question • Ina card game, two players are each dealt 26 cards from a deck of 52. Thirteen of the cards have a club on them. Which event is more likely: getting dealt all of the clubs, or getting none of them?
- 10. Brainteaser question If youmultiplied the first 1000 prime numbers together, what digit would be in the ones place (the last digit of the number)?
- 11. Math puzzle • Fivepeople order a square pizza. The first person dives in an eats a quarter of the pizza. The other four people have to divide the remaining three- fourths into four equal and identically shaped slices. The cuts must be straight. How must they cut the remaining pizza in order to produce four identical slices?
Editor's Notes
- #3 Brainteaser answer100 chocolate bars have 100 wrappers, which can be traded for 10 free bars. The wrappers for the free bars can then be traded for one more free bar (and an extra wrapper). 100 + 10 + 1 = 111 chocolate bars.
- #4 Brainteaser answerA line can only have one of each digit, so the biggest sum is:1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45
- #5 Brainteaser answerThere are five different ways to make $1.10 with seven coins. You can’t use a $1 coin – it’s too big. You can’t use two 50c coins either. With one 50c coin, you can make:50c, 20c, 20c, 5c, 5c, 5c, 5c50c, 20c, 10c, 10c, 10c, 5c, 5c50c, 10c, 10c, 10c, 10c, 10c, 10cWith no 50c coins, you can make:20c, 20c, 20c, 20c, 20c, 5c, 5c20c, 20c, 20c, 20c, 10c, 10c, 10cAnd that’s all the combinations you can make.
- #6 Brainteaser answerIt is possible if the date is 1 January, and George’s birthday is on 31 December. Then last year he turned 13, this year he’ll turn 14 and next year he’ll turn 15.
- #8 Brainteaser answerThey are in alphabetical order!(Eight, five, four, nine, one, seven, six, ten, three, two, zero.)
- #9 Brainteaser answerEach student sends one letter to each person in the class except themselves. If there were 6 people in the class, each would send 5 letters, which makes 6 x 5 = 30 letters in total.306 = 18 x 17, so 18 students each sent 17 letters to make the total.A good place to start with this puzzle would be calculating the square root of 306. Since the number of students and the number of letters that each student sends are very close, it will give you a good estimate of the number of people in the class.
- #10 Brainteaser answerIf one player has all the clubs, then the other has none – you can’t have one without the other. So both outcomes are equally likely!
- #11 Brainteaser answerThe first and third primes are 2 and 5. If you multiply anything by 2 and 5, it will be divisible by 10, and that means it ends in a 0!