Đề vòng chung kết Olympic TIMO 2020-2021 Khối 1 (Kèm đáp án)

 THAILAND INTERNATIONAL 
 MATHEMATICAL OLYMPIAD 
 FINAL ROUND 2020 – 2021 
 Primary 1 
 Time allowed: 120 minutes 
 Question Paper 
 Instructions to Contestants: 
1. Each contestant should have ONE Question-Answer Book which CANNOT be 
 taken away. 
2. There are 5 exam areas and 6 questions in each exam area. There are a total of 30 
 questions in this Question-Answer Book. Each question carries 5 marks. Total 
 score is 150 marks. No points are deducted for incorrect answers. 
3. All answers should be written on ANSWER SHEET. 
4. NO calculators can be used during the contest. 
5. All figures in the paper are not necessarily drawn to scale. 
6. 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. 
7. This Question-Answer Book will be collected at the end of the contest. 
 DO NOT turn over this Question-Answer Book without approval of the examiner. 
 Otherwise, contestant may be DISQUALIFIED. 
 1 
 All answers should be written on the ANSWER SHEET. 
10. Find the value of 22 37 28 . 
11. If A is a 1-digit number, what is the value of A if the equation below is 
 correct? 
 A 
 A + + A A = 1 6 
12. Find the value of 24 25 26 27 28 16 17 18 19 20 . 
 Number Theory 
13. By observing the numbers, which odd number is the greatest? 
 23、27、52、41、72、24、50 
14. Determine the result of AAAA 3 2 4 3 5 4 is an odd or even 
 number. 
15. The numbers below follow the arithmetic sequence, what is the 17th number? 
 243、231、219、207、195、 
16. Find the largest 2-digit odd number whose the unit digit is smaller than the 
 tens digit. 
17. In a Science test, the total score of 4 students is 49. No students share the same 
 score and no one got zero. If Andy got the lowest score among them, find the 
 highest possible score of Andy? 
18. According to the pattern shown below, what is the number in the space 
 provided? 
 4 、 12 、 20 、 28 、 36 、 44 、 __ 、. 
 Geometry 
19. It is known that figure 1 is formed by 4 cubes. At least how many cube(s) is / 
 are there in figure 2? 
 3 
 All answers should be written on the ANSWER SHEET. 
24. According to the pattern shown below, what is the figure in the space 
 provided? 
 ▓▲●▲▓▓▲●▲▓▓▲●▲▓▓__ ● 
 Combinatorics 
25. According to the following answers, how many 1-digit number(s) is / are 
 there? 
 46 , 94 , 84 , 17 5, 56 , 11 7, 16 5 
26. Bruce has 4 $5 coins. At most how many $2 coin(s) can he exchange? 
27. Which number below is the smallest? 
 20203154 、 20204651 、 20214320 、 20193451 
28. Choose 4 digits, without repetition, from 0, 2, 3, 5 and 7 to form two 2-digit 
 numbers and add them up. What is the maximum value of the sum? 
29. How many 2-digit number(s) having the tens digit that is less than 5 is / are 
 there? 
30. According to the following sequence for first 37th terms, how many odd 
 number(s) is / are there? 
 3, 1, 4, 5, 9, 14, 23, 37,  
 ~ End of Paper ~ 
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