Prime numbers - practice for 12 year olds - page 5 of 14
Number of problems found: 272
- Two hundred
Two hundred ten athletes competed in three athletics races on three fields. One hundred five athletes competed in the first, 60 in the second, and everyone else in the third. On the individual courts, the athletes were divided into groups. Although compet - The classroom
The classroom is 9 meters long. The width of the classroom is smaller and can be passed in equally long steps of 55 CM or 70 CM. Find the width of the classroom. - Together 36443
Three buses are leaving the bus station. The circuit of the first bus lasts 1 hour, 24 minutes, the second 150 minutes, and the third 2 hours. When will they leave together? - Three-fifths 34771
Calculate three-fifths of the ratio of the product and the sum of all prime divisors of 240. - Square gardens
The gardening colony with dimensions of 180 m and 300 m is to be completely divided into equally large square areas with the largest possible area. Calculate how many such square areas can be obtained and determine the square's side length. - Prime divisors
Find 2/3 of the sum's ratio and the product of all prime divisors of the number 120. - Summer camp
Some boys or girls signed up for the summer camp, which has a maximum capacity of 200 children. The main leader noticed that during the evening start, he could arrange the participants exactly in the twelve-step, sixteen-step, or eighteen-step, and no one - Tractor wheels
The tractor's front wheel has a circumference of 18 dm and the rear 60 dm. We will make a red mark on the lowest point of both wheels. The tractor then starts. At what distance from the start will both marks appear identically at the bottom again? - Three
Three buses follow the same circular route. The first driver is the slowest because he has many stops, and it takes him 90 minutes to cross the route. The second driver will pass the circuit in 1 hour. The third driver has the fewest stops, and the circui - Pegs
From two sticks 240 cm and 210 cm long, it is necessary to cut the longest possible pegs for flowers so that no residues remain. How many pegs will it be? - Divisible by nine
How many three-digit natural numbers in total are divisible without a remainder by the number 9? - Two gears
Two gears with 13 and 7 teeth rotate locked into each other. We want both wheels to be in the starting position again. How many turns does a big wheel have to make? - Three ships
There are three ships moored in the port, which sail together. The first ship returns after two weeks, the second after four weeks, and the third after eight weeks. In how many weeks will the ships meet in the port for the first time? How many times have - Returning 27121
Two gears – one smaller and one larger rotate so that the teeth of both wheels mesh together. The first wheel has 18 teeth, the second 27. How often does each wheel turn before returning to its starting position? - Intervals 27081
Three lines depart from the bus terminal at 5:30 in the morning. At what time will all three buses meet again at the terminus first, if one has intervals of 10 minutes, the second 12 minutes, and the third 15 minutes? - Divisors of 560
Which of the numbers 5, 6, 7, 14, and 15 are divisors of 560? Please justify the answer. - The missing digit
Complete the missing digit in the number 3 ∗ 43 to form a number divisible by three. If there are multiple options, list them all. (The omitted digit is marked with the symbol ∗. ) Answers must be justified! - Prime factors
Factor the number 6600 into the product of prime numbers. - Ratio
Alena collected 7.8 kg of blueberries, 2.6 kg of blackberries, and 3.9 kg of cranberries. Express the ratio in the smallest natural numbers in this order. - Simultaneously 25521
People travel to the seaside in Greece for 8-day, 10-day and 12-day stays. An assigned delegate flies there and back with each group of passengers. On May 1, all three groups and their delegates will fly to the sea simultaneously. When will all three dele
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