Prime numbers - practice for 14 year olds - page 4 of 5
Number of problems found: 99
- Different 5402
Adélka had two numbers written on the paper. When she added their greatest common divisor and least common multiple, she was given four different numbers less than 100. She was amazed that if she divided the largest of these four numbers by the least, she - Minutes 5310
They had three tower clocks in the city. Some went right, the others were 10 minutes ahead of the day, and the thirds were 12 minutes late each day. One day they struck all the clocks at noon at once. How long will it be like this again? - Sales of products
For 80 pieces of two quality products, the total sales are 175 Eur. Suppose the first quality product was sold for n EUR per piece (n natural number) and the second quality product after 2 EUR per piece. How many pieces of the first quality were sold? - Individual 4881
There are 32 rooms in the hostel. Some have double beds, others have four beds and the rest have 7 beds. There are a total of 139 beds in the hostel. How many are there if a two-digit number gives the numbers of individual species?
- Rectangular 4819
Divide the rectangular meadow with dimensions of 1280m and 320m into a square shepherd with the longest possible side of the square. How many square pastures did you divide the meadow? - Pardubická 4651
Jirka decided to divide the winnings from the bet in Velká Pardubická between himself and his three younger brothers according to age in the ratio of 2:3:5:7. They paid each amount in whole crowns. One of the amounts was CZK 679. How big was the win? - Expression 4451
Find the largest natural number d that has that property for any natural number the number n is the value of the expression V (n) = n ^ 4 + 11n²−12 is divisible by d. - Probability 4020
There are numbers from 1 to 20 in the hat. What is the probability that we will pull out from the hat: a / one-digit number b / prime number c / number greater than 11 d / a number divisible by six Thank you - Z9-I-4
Kate thought of a five-digit integer. She wrote the sum of this number and its half in the first line of the workbook. On the second line, write a total of this number, and its one fifth. She wrote a sum of this number and its one nines on the third row.
- Infinitely 3818
We have 2 numbers. If we multiplied the first number's third root by the second number's square root, we would get the number 18. Determine these 2 numbers. Calculate only the integer solution if the problem has infinitely many solutions in the set of rea - One-sixth 3279
If I had half as many nuts as I have now, I would have the same as Vendulka. If Vendulka had a third less than she has now, she would have the same size as me. If she had one-sixth less than she has and gave me that part, we would have the same amount. Ho - Four classses
Students of all 7, 8, and 9 classes in one school may take up 4,5,6, and 7 abreast, and nobody will be left. How many is the average count of pupils in one class if there are always four classes in each grade? - Amazing number
An amazing number is a name for such an even number, the decomposition product of prime numbers has exactly three, not necessarily different factors, and the sum of all its divisors is equal to twice that number. Find all the amazing numbers. - Shepherd
The shepherd has fewer than 500 sheep; where they can be up to 2, 3, 4, 5, 6 row is always one remain, and as can be increased up to 7 rows of the sheep, and it is not increased any ovine. How many sheep have a shepherd?
- Ski tow
The ski club has 168 pupils and uses a lift with 60 seats, while students always follow the same sequence in filling seats. How often while riding a ski lift has the skier sitting in the same seat as the first run? - Grandson and granddad
Grandson with grandpa, they counted how many years have together. Their product is 365. How many years is the sum of their years? - 9.A
Class 9A attends more than 20 students but fewer than 40 students. A third of the pupils wrote a math test to mark 1, the sixth to mark 2, and the ninth to mark 3. No one gets mark 4. How many students of class 9A wrote a test to mark 5? - Numbers
Write the smallest three-digit number in divisions 5 and 7, and gives the rest 2. - Two months
Mars has two months, Phobos and Deimos. Phobos orbit around Mars in 7 hours 39 minutes, and Deimos in 30 hours 14 minutes. How long will the relative positions of the three celestial bodies repeat?
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