Combinatorics - practice for 11 year olds
Number of problems found: 30
- Choices 82334
There are 15 black and 15 white balls in an opaque bag. Elenka took one ball out of the bag three times. what choices of the three balls could she choose? - Three-digit number
How many three-digit natural numbers can we form from the digits 0, 1, and 2 if the numerals can be repeated in these numbers? - Double six-six
What is the probability that a player in the games of ludo will throw a double six twice? - Chess competition
Four chess players took part in the competition. How many matches have taken place if every chess player has played with everyone just once? - Certificate 6740
There are 19 children in class 6A, 7 subjects, and no one has a worse grade than a three. Can each of them have a different certificate? How many would have to be in the class so that everyone could not have another report card? - Options 3572
We roll three dice. Write down all the feast options. - Roll the dice
What is the probability that if we roll the dice, a number less than five falls? - Football team
The football team has black, purple, and orange shirts, blue and white shorts, and striped and gray socks. How many different outfits may players start? - Three digits number 2
Find the number of all three-digit positive integers that can be put together from digits 1,2,3,4 and which are subject to the same time has the following conditions: on one position is one of the numbers 1,3,4, on the place of hundreds 4 or 2. - Three-digit 45361
How many different three-digit numbers divisible by five can we create from the digits 2, 4, and 5? The numerals can be repeated in the created number. - The dice
Find the probability that a number divisible by two or three will fall when the dice are rolled. - Five-digit
Find all five-digit numbers that can be created from number 12345 so that the numbers are not repeated and then numbers with repeated digits. Give the calculation. - Attempts 3460
How many attempts do I need to guess the 3-digit PIN to be sure I can guess it? - Digits
How many odd four-digit numbers can we create from digits: 0, 3, 5, 6, and 7? (a) the figures may be repeated (b) the digits may not be repeated - What fraction
What fraction of numbers 1 to 30 is prime? - Together 70124
Twins Ela and Nela came to the cinema together with their friend Hela. Only the first 10 seats in the third row are free. How many ways can they be seated if the twins want to sit next to each other, with Nela always to Ela's left and Hel right next to on - Seven-segmet
Lenka is amused that he punched a calculator (seven-segment display) number and used only digits 2 to 9. Some numbers have the property that She again gave their image in the axial or central symmetry some number. Determine the maximum number of three-dig - Differently 69514
Gabika wants to wear pants, a blouse, a skirt, and a T-shirt to the party. She has two pairs of pants, 3 blouses, 3 skirts, and 4 T-shirts to choose from. How many parties can she attend if everyone wants to go dressed differently? - Birthday 6277
Peter got a new bike for his birthday. His bike was equipped with many gears. How many gear options does Peter have if you have three wheels at the front and eight wheels at the back? List them all - Twins with friend
The twins Danka and Janka went to the cinema with their friend Betka. Only six seats in the second row were available in the cinema. The twins want to sit next to each other. Danka is always to the right of Janka, and Betka is near one of them. How many m
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