Natural numbers - problems

  1. Game 27
    dice_4 Susan wanted to play the game. In the beginning, the first says a number from 1 to 8. Then the second player adds a number from 1 to 5 and tells the sum. Again, the Susan adds a number from 1-5 and say sum and etc. . . The winner must say the number 27. Wh
  2. Hectares
    tractor_8 The tractor plows the first day of 4.5ha, the second day 6.3ha and the third day 5.4ha. It worked whole hours a day, and its hourly performance did not change and was the highest of the possible. How many hectares did it plow in one hour (what is it perfor
  3. MO C–I–1 2018
    numbers_49 An unknown number is divisible by just four numbers from the set {6, 15, 20, 21, 70}. Determine which ones.
  4. MO Z8-I-1 2018
    age_6 Fero and David meet daily in the elevator. One morning they found that if they multiply their current age, they get 238. If they did the same after four years, this product would be 378. Determine the sum of the current ages of Fero and David.
  5. Clubhouse
    stol_2 There were only chairs and table in the clubhouse. Each chair had four legs, and the table was triple. Scouts came to the clubhouse. Everyone sat on their chair, two chairs were left unoccupied, and the number of legs in the room was 101. How many chairs w
  6. Age
    age_5 In 1960 my age was equal to the digits sum of the year of my birth. What is my age now?
  7. Mba studium
    skola_18 At MBA school, fourth-year students can choose from three optional subjects: a) mathematical methods, b) social interaction, c) management Each student studies one of these subjects. The mathematical methods studied 28 students, the social interaction 27.
  8. Two numbers 7
    numbers_49 The sum of two consecutive even numbers is 30. Find the numbers.
  9. Dance ensemble
    dancers_1 The dance ensemble took the stage in pairs. During dancing, the dancers gradually formed groups of four, six and nine. How many dancers have an ensemble?
  10. Clock's gears
    orloj In the clock machine, three gears fit together. The largest has 168 teeth, the middle 90 teeth, and the smallest 48 teeth. The middle wheel turns around its axis in 90 seconds. How many times during the day do all the gears meet in the starting position?
  11. Classmates
    meter_13 Roman is ranked 12th highest and eleventh lowest pupil. How many classmates does Roman have?
  12. Inverted nine
    In the hotel,, Inverted nine" each hotel room number is divisible by 6. How many rooms we can count with three-digit number registered by digits 1,8,7,4,9?
  13. Progression
    sequence_geo_10 12, 60, -300,1500 need next 2 numbers of pattern
  14. Brick
    brick One brick is 6 kg and half a brick heavy. What is the weight of one brick?
  15. Chocolate
    cokolada Randy bought 6 same chocolates for 6 Eur. How many euros will he pay for 25 chocolates?
  16. Divisibility
    divisibility Is the number 761082 exactly divisible by 9? (the result is the integer and/or remainder is zero)
  17. Monkey
    monkey Monkey fell in 38 m deep well. Every day her scramble 3 meters, at night dropped back by 2 m. On that day it gets hangover from the well?
  18. Diophantus
    diofantos_1 We know little about this Greek mathematician from Alexandria, except that he lived around 3rd century A.D. Thanks to an admirer of his, who described his life by means of an algebraic riddle, we know at least something about his life. Diophantus's youth l
  19. Z9-I-4
    numbers_30 Kate thought a five-digit integer. She wrote the sum of this number and its half at the first line to the workbook. On the second line wrote a total of this number and its one fifth. On the third row she wrote a sum of this number and its one nines. Fi
  20. No. of divisors
    triangle_div How many different divisors has number ??

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