# Reason + variations - math problems

#### Number of problems found: 48

• Number 4
Kamila wrote all natural numbers from 1 to 400 inclusive. How many times did she write the number 4?
• Big numbers
How many natural numbers less than 10 to the sixth can be written in numbers: a) 9.8.7 b) 9.8.0
• Wagons
We have six wagons, two white, two blue, and two red. We assemble trains from them, wagons of the same color are exactly the same, so if we change only two white wagons on a train, it's still the same train, because I don't know any different. How many di
• Research in school
For particular research in high school, four pupils are to be selected from a class with 30 pupils. Calculate the number of all possible results of the select and further calculate the number of all possible results, if it depends on the order in which th
• Gold, silver, bronze
How many ways can we divide gold, silver, bronze medails if there are 6 people competing?
• Five letters
How many ways can five letters be arranged?
• Boys and girls
There are 20 boys and 10 girls in the class. How many different dance pairs can we make of them?
• Year 2020
The four-digit number divided by 2020 gives a result of 1, **. (Can not be in form 1,*0. ) Write all the options.
• Two groups
The group of 10 girls should be divided into two groups with at least 4 girls in each group. How many ways can this be done?
There are 15 boys and 12 girls at the graduation party. Determine how many four couples can be selected.
• One three
We throw two dice. What is the probability that max one three falls?
• Bookshelf and books
How many ways can we place 7 books in a bookshelf?
• A jackpot
How many times must I play this jackpot to win? A jackpot of seven games having (1 X 2), i. E. , home win or away win.
• Pages counting
There are pages numbered from 2 to 104 in the book. How many digits have to be printed to number the pages?
• 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?
• PIN code
PIN on Michael credit card is a four-digit number. Michael told this to his friend: • It is a prime number - that is, a number greater than 1, which is only divisible by number one and by itself. • The first digit is larger than the second. • The second d
• To improve
To improve her handwriting Paula practices writing the numbers 1 to 200 in words. How many times will she have written the word "one" in all?
• Sweater
Dana confuses sweater and wool has a choice of seven colors. In how many ways she can choose from three colors to the sleeves?
• Lunch
Seven classmates go every day for lunch. If they always come to the front in a different order, will be enough school year to take of all the possibilities?
• Seven
Seven friends agree to send everyone a holiday card. How many postcards were sent?

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