Mathematical Olympiad - practice for 14 year olds
Number of problems found: 64
- Two-digit 82521
Karel had to multiply two two-digit numbers. Out of care, he changed the order of the digits in one of the factors and got a product that was 4,248 less than the correct result. What is the correct result? How much should Karl have earned? - Subtract 82333
I think of three numbers; when I add them, I get 16; when I subtract the third from the sum of the first two numbers, I get 10; when I subtract the second from the sum of the first and third numbers, I get 8. Which numbers do I think? - Quadrilateral calc
The square ABCD is given. The midpoint of AB is E, the midpoint of BC is F, CD is G, and the midpoint of DA is H. Join AF, BG, CH, and DE. Inside the square (approximately in the middle), the intersections of these line segments form a quadrilateral. Calc - Intersection 81017
There are also two equilateral triangles ABC, and BDE, such that the size of the angle ABD is greater than 120° and less than 180° points C and E lie in the same half-plane defined by the line AD. The intersection of CD and AE is marked F. Determine the s
- Respectively 80982
The vertices of the square ABCD are joined by the broken line DEFGHB. The smaller angles at the vertices E, F, G, and H are right angles, and the line segments DE, EF, FG, GH, and HB measure 6 cm, 4 cm, 4 cm, 1 cm, and 2 cm, respectively. Determine the ar - Grandchildren 80639
The average age of the grandfather, grandmother, and their five grandchildren is 26 years. The average age of the grandchildren themselves is 7 years. Grandma is a year younger than grandpa. How old is grandma? - Smallest z9
Find the smallest positive numbers a and b for which 7a³ = 11b⁵ - Differences 80551
Bolek and Lolek each had their own arithmetic sequence. Both Lolek and Bolek's sequence started with the number 2023 and ended with the number 3023. The two sequences had 26 numbers in common. The ratio of Bolek's and Lolka's difference was 5:2. What is t - Determine 55891
Determine the number of nine-digit numbers in which each of the digits 0 through 9 occurs at most once and in which the sums of the digits 1 through 3, 3 through 5, 5 through 7, and 7 to the 9th place are always equal to 10. Find the smallest and largest
- Two ports
Between the ports of Mumraj and Zmatek, two ships commute along the same route. They spend negligible time in ports, turn around immediately, and continue sailing. At the same time, a blue ship departs from the port of Mumraj, and a green ship departs fro - Coloured numbers
Mussel wrote four different natural numbers with colored markers: red, blue, green, and yellow. When the red number divides by blue, it gets the green number as an incomplete proportion, and yellow represents the remainder after this division. When it div - Squirrels
The squirrels discovered a bush with hazelnuts. The first squirrel plucked one nut, the second squirrel two nuts, and the third squirrel three nuts. Each new squirrel always tore one nut more than the previous squirrel. When they plucked all the nuts from - Construct 11511
Construct the diamond ABCD so that its diagonal BD is 8 cm and the distance of apex B from the line AD is 5 cm. Specify all options - Subtract 10001
For five whole numbers, if we add one to the first, multiply the second by the second, subtract three from the third, multiply the fourth by four, and divide the fifth by five, we get the same result each time. Find all five of the numbers that add up to
- Circumference 9811
Kristýna chose a certain odd natural number divisible by three. Jakub and David then examined triangles with a circumference in millimeters equal to the number selected by Kristýna and whose sides have lengths in millimeters expressed by different integer - Complaining 9611
Ondra, Matěj, and Kuba are returning from collecting nuts. They have a total of 120. Matěj complains that Ondra has the most as always. The father orders Ondra to sprinkle it on his Matěj so that the number of nuts doubles. Now Cuba is complaining that he - Three-digit 9601
Majka researched multi-digit numbers, in which odd and even numbers alternate regularly. Those who start with an odd number are called comics, and those who start with an even number are called cheerful. (For, number 32387 is comic, and number 4529 is hil - Divisible 9331
The number X is the smallest natural number whose half is divisible by three, a third is divisible by four, a quarter is divisible by eleven, and its half gives a remainder of 5 when divided by seven. Find this number. - Identical 8831
In the triangle ABC, the point P lies closer to point A in the third of the line AB, the point R is closer to the point P in the third of the line P, and the point Q lies on the line BC so that the angles P CB and RQB are identical. Determine the ratio of
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