Write down the answer in the simplest form. If the calculation result is a fraction, please write down the answer as a proper or mixed fraction, decimal figure is also accepted. Marks will NOT be given for incorrect unit. O L Y M P I A D C H A M P I O N E D U C A T I O N C E N T R E Room 309-310, 8 Jordan Road, Yau Ma Tei, Kowloon, Hong Kong SAR, CHINA Tel (852) 3153 2028 / 9310 1240 Fax (852) 3153 2074 Website: www.olympiadchampion.com Email: olympiadchampion@gmail.com GUANGDONG-HONG KONG-MACAO GREATER BAY AREA MATHEMATICAL OLYMPIAD 2019 (GREATER BAY AREA REGION) Primary 4 Question Paper Time allowed: 75 minutes Instructions to Contestants: 1. Each contestant should have ONE Question Book which CANNOT be taken away. 2. There are 3 sections in this exam. Section A consists of 10 questions. Each carries 4 marks. Section B consists of 10 questions. Each carries 5 marks. Section C consists of 5 questions. Each carries 7 marks. The total number of questions is 25. Total score is 125 marks. No points are deducted for incorrect answers or empty answers. 3. NO calculators can be used during the contest. All figures in the paper are not necessarily drawn to scale. 4. This Question Book will be collected at the end of the contest. THIS Question Book CANNOT BE TAKEN AWAY. DO NOT turn over this Question Book without approval of the examiner. Otherwise, contestant may be DISQUALIFIED. All answers should be written on the ANSWER SHEET. Write down the answer in the simplest form. If the calculation result is a fraction, please write down the answer as a proper or mixed fraction, decimal figure is also accepted. Marks will NOT be given for incorrect unit. Section A: 1st to 10th Question (Each carries 4 marks) 1) Find the value of 4446 18  . 2) Find the highest common factor of 341 and 434. 3) Find the least common multiple of 27 and 24. 4) How many positive integers can be divisible by both 2 or 3 with 100? 5) Now there is an arithmetic sequence: 3, 6, 9, …, 333. How many numbers are there? 6) A four-digit number is divided by 7 to get a reminder of 3. Find the maximum value of this four-digits number. 7) Find the average of these 8 numbers: 10, 25, 47, 23, 32, 87, 1, 39. 8) Find the value of 13 26 13 32 13 8      . 9) Ming’s age is one fifth of mum’s age 3 years ago. Ming is born when mum was 19 years old. How many years later mum’s age will be 3 times of Ming’s age? 10) Box A is 1 kg and box B is 3 kg. Now we have 20 boxes with 52 kg in total. How many box A we have? All answers should be written on the ANSWER SHEET. Write down the answer in the simplest form. If the calculation result is a fraction, please write down the answer as a proper or mixed fraction, decimal figure is also accepted. Marks will NOT be given for incorrect unit. Section B: 11th to 20th Question (Each carries 5 marks) 11) Tomorrow is Monday. Which day of the week will 200 days later be? 12) Refer to the puzzle, each English letter represents different numbers. Find the value of ABCD. A B C D A B C A B + A 2 0 4 6 13) Find the value of 23 30 37 ... 163 170 177       . 14) In a Mathematics test, the average marks for 30 students are 60. If we are not counting 10 students with 0 marks, what will the average marks be? 15) Find the last digit of 1 3 7 9 ... 91 93 97 99         . 16) Refer to the figure below, how many rectangles are there with 2 black dots? All answers should be written on the ANSWER SHEET. Write down the answer in the simplest form. If the calculation result is a fraction, please write down the answer as a proper or mixed fraction, decimal figure is also accepted. Marks will NOT be given for incorrect unit.   Question 16 17) If a 10-digit number 20190217AB is divisible by 66, find the value of A B . 18) Find the value of 182 9 91 3 26 18      . 19) Numbers are drawn from 50 integers 1 to 50. At least how many numbers are drawn at random to ensure that there are two numbers whose difference is 13? 20) If A B  589 and A, B are positive integers, find the minimum value of A B . All answers should be written on the ANSWER SHEET. Write down the answer in the simplest form. If the calculation result is a fraction, please write down the answer as a proper or mixed fraction, decimal figure is also accepted. Marks will NOT be given for incorrect unit. Section B: 21st to 25th Question (Each carries 7 marks) 21) 201 8 ab c can be divisible by 165 and abc   . Find the value of abc   . 22) There are 5000 of each red, blue and yellow sock in a bag. Each time you draw one randomly from the bag. At least how many times required to draw to ensure you have a pair of every color? 23) Find the value of 111011 111211  . 24) In a Chinese test, the average marks for 50 students are 30. The lowest mark is 10. At most how many students get 100 marks? 25) Find the value of 2 2 2 2 2 2 565 564 563 562 561 560      . ~ End of Paper ~