Which gives the largest answer?
What is the difference between the sum of the first 2012 even positive numbers and the sum of the first 2012 odd positive numbers?
A man is eating a pizza.
During the first day he eats a half of the pizza.
On the second day he eats 1/3 of the remaining part of the pizza.
The third day he eats 1/4 of what is left, and the fourth day he eats 1/5 of what still remains.
He then stops because the last piece was not fresh.
What fraction of the original pizza is still available?
An abundant number is a positive integer whose factors (other than the number itself) have a sum greater than the number.
Which number is not abundant?
When freezing, milk increases its volume by 1/15.
How will the frozen milk volume decrease when it melts?
A number is said to be perfect if it is equal to the sum of its proper divisors, that is all divisors excepting the number itself.
For example, 6 is a perfect number because 1 + 2 + 3 = 6 .
What is the largest 3-digit perfect number?
A prime number is an integer number that has no positive divisors other than 1 and itself.
Which is not a prime number?
The North American emergency telephone number is 911.
It is a prime number.
A prime number is an integer that has no positive divisors other than 1 and itself.
What is the next prime number?
Multiply all the digits of each license plate without using a calculator.
Find the plate with the smallest total.
What is the smallest possible difference between two integer numbers that, when multiplied together, produce12345?
Fill in each empty place between the numbers with one of the symbols +, -, x or /, with each symbol used exactly once.
No parentheses are allowed.
What is the least possible absolute value of the result?
Write natural numbers 1, 2, . . .100 in a row so that the difference between any two adjacent numbers is smaller than N.
Find the maximum possible N.
In a class, 7 students walk to school, two fifths ride the bus, and 32% are dropped off by their parents.
What number is the largest?
In a class, 7 students walk to school, two fifths ride the bus, and 32% are dropped off by their parents.
How many students ride the bus?
How many digits are there in the largest positive integer, in which each digit is at least the sum of all the digits to its left?
What is the smallest result that can be achieved?
AB6 + BC7
Different letters in the expression are replaced with different numbers from 0 to 9 and there are no leading zeros.
The question is typical for PISA Test.
PISA stands for Programme for International Student Assessment.
The maximum capacity of the Wembley Stadium, London, England, is 90,000.
The stadium contains 2,618 toilets, more than any other venue in the world.
There are 78,540 people in the stadium now.
If they all go to the toilets and they are evenly distributed, how long will be the queue?
We suppose that there is 1 seat per toilet.
The ratio of two numbers is 3 : 5.
The difference between the numbers is 8.
What is the sum of the two numbers?
Gerry writes the first 5 integers.
He puts either sign "+" or "x" between the numbers.
What is the largest result he can get?
He does not use parentheses (brackets).
How many positive integers that are strictly less than one hundred are evenly divisible by both 2 and 3?
Put four operations signs between the numbers 5, 4, 3, 2, and 1 to make the lowest possible result.
What will it be?
Don't change the order of the numbers, use all four signs, and don't use brackets.
Spotting patterns is very important.
Can you spot which number doesn't fit the pattern?
1, 2, 5, 14, 42, 122, . . .
Author: Leslie Green
Cross out 5 digits from the number
54321543215432154321
so that the remaining number is as small as possible.
What are the first five digits of the result?
Do this in your head. No pen, paper, or calculator.
Start with 3
multiply the result by 3
add one
multiply the result by 3
add one
Which is the correct answer?
Which gives the smallest answer?
What is 111% of a number, if 132 is 11% of that number?
How many 2-digit integers are there in which the sum of the digits is equal to 6?
Evaluate: 
If you write all of the whole numbers from 1 through 1000, how many numbers have the digit 4? 
Work out the sum of all the integers below 100.
On this target, I scored exactly 90. 
How many positive integer numbers are twice the sum of their digits?
January 1st, 2014 was a Wednesday. 
Use four 9's and any math signs to make 100. 
Find 
If A, B, and C are different digits, how many different solutions does the number puzzle have?