These questions are actually meant for 12 year olds but you won’t believe it. All questions taken from the 2014 junior maths challenge paper.
1. What is (999 âˆ’ 99 + 9) Ã· 9?
One method is to first work out the value of the expression in the brackets and then dividethe result by 9. This gives(999 âˆ’ 99 + 9) Ã· 9 = 909 Ã· 9 = 101.Alternatively, we can first divide each number in the bracket by 9 and then evaluate theresulting expression. This gives(999 âˆ’ 99 + 9) Ã· 9 = (111 âˆ’ 11 + 1) = 101.
2. How many minutes are there in 1/12 of a day?
There are 24 hours in a day. 24 divided by 12 = 2. And in 2 hours there are 120 minutes. Duh!
3. In my row in the theatre the seats are numbered consecutively from T1 to T50. I am sitting in seat T17 and you are sitting in seat T39. How many seats are there between us?
The seats between us are numbered from T18 up to T38. So the seats between us arethe 38 seats from T1 up to T38, other than the 17 seats from T1 up to T17. So there are38 âˆ’ 17 = 21 seats between us…OBVIOUSLY!
4. The number 987,654,321 is multiplied by 9. How many times does the digit 8 occur in the result?
Yeah for this one you just have to be real good at long multiplication. Sorry.
5. What is the difference between the smallest 4-digit number and the largest 3-digit number?
The smallest 4-digit number is 1000. The largest 3-digit number is 999. So their differenceis equal to 1000 âˆ’ 999 = 1.OF COURSE.
6. The diagram shows a square divided into strips of equal width. Three strips are black and two are grey. What fraction of the perimeter of the square is grey?
Two sides of the square are wholly black, and 2/5of two sides are grey. So the length of theperimeter that is grey is equal to 2 Ã— 2/5 = 4/5 of the length of one side. The length of the perimeter is 4 times the length of one side. So the fraction of the perimeter that is grey is the sum shown in the image.
7. What is 2014 âˆ’ 4102 ?
It is easier to subtract the smaller number, 2014, from the larger number, 4102. Now4102 âˆ’ 2014 = 2088and so2014 âˆ’ 4102 = âˆ’2088.I MEAN DUH.
8. How many prime numbers are there in the list 1, 12, 123, 1234, 12 345, 123 456 ?
It is important to remember that we do not regard 1 as a prime number.We see that 12, 1234 and 123 456 are not prime numbers because they are divisible by 2. Also, 123 is not a prime number because it is divisible by 3, and 12 345 is not a primenumber because it is divisible by 5.So there are no prime numbers in the list.That one is quite tricksy tbh.
9. Triangles XYZ and PQR are drawn on a square grid. What fraction of the area of triangle XYZ is the area of trianglePQR?
Calculate the area of both triangles using the formula: Area = 1/2 (base x height) And then work out the fraction by dividing the area of PQR by XYZ.
10. An equilateral triangle is surrounded by three squares, as shown. What is the value of x?
We have labeled the diagram to help explain this answer. PR = RS because they are sides of a square, and RS = RT because they are sides of an equilateral triangle. RQ = RT because they are also sides of a square. Therefore RQ = PR. And because RQ and PR are sides of an isosceles triangle, angle RPQ = angle RQP. Right now remember that angles of a triangle totaled equals 180Â°. And angles of a square are all 90Â° and angles of an equilateral triable are all 60Â°. Following? Good. So all the angles at point R must equal 360Â°. So…Angle PRQ = 360 — (90 + 90 + 60) = 120. Therefore x = (360 — 120) / 2 = 30.WOOO WE DID IT.
11. The first two terms of a sequence are 1 and 2. Each of the following terms in the sequence is the sum of all the terms which come before it in the sequence. Which of these is not a term in the sequence?
- 48 Read more: http://www.buzzfeed.com/floperry/maths-challenge-is-impossible