ID 685

ID 688

ID 756

ID 766

What is 111% of a number, if 132 is 11% of that number?

ID 1020

How many 2-digit integers are there in which the sum of the digits is equal to 6?

ID 1070

If 120 is divided into three parts proportional to 7, 8 and 9, then the largest number is

ID 1207

Evaluate:

1000000012 – 999999992

ID 1212

How many digits are in the product of

2101 and 599?

ID 1554

If you write all of the whole numbers from 1 through 1000, how many numbers have the digit 4?

ID 1839

How much is

0 - 1 + 10 - 100 + 1000 - . . . -1010+1011

ID 1881

What is the difference between the sum of the first 2012 even positive numbers and the sum of the first 2012 odd positive numbers?

ID 1980

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?

ID 2028

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?

ID 2229

When freezing, milk increases its volume by 1/15.

How will the frozen milk volume decrease when it melts?

ID 2268

Work out the sum of all the integers below 100.

ID 2276

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?

ID 2283

A prime number is an integer number that has no positive divisors other than 1 and itself.

Which is not a prime number?

ID 3221

If 168 is divided into three parts proportional to 7, 8 and 9, then the smallest number is

ID 3318

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?

ID 3356

Sebastian achieved these scores in his exams.

Which was his worst result?

ID 3392

Multiply all the digits of each license plate without using a calculator.

Find the plate with the smallest total.

ID 3412

On this target, I scored exactly 90.

How many shots did I fire?

ID 3432

How many 2-digit integers are there in which the sum of the digits is equal to 6?

ID 3537

How many positive integer numbers are twice the sum of their digits?

ID 3649

What is the smallest possible difference between two integer numbers that, when multiplied together, produce12345?

ID 3774

How many of the three-digit integers are multiples of the first five positive integers?

ID 3779

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?

ID 3784

Find the sum of the first 100 odd positive numbers:

1 + 3 + . . .

ID 3918

Find the average of all positive integers divisible by 3 and smaller than 1000.

ID 3964

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.

ID 4039

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?

ID 4040

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?

ID 4051

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?

ID 4182

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.

ID 4235

If the sum of 999 positive integers is equal to 1000 what is their product?

ID 4297

What gives the largest result?

ID 4376

Which number could not be written as a sum of 3 consecutive numbers?

ID 4501

Find the first of the four consecutive integer numbers if their sum is -66.

ID 4537

January 1st, 2014 was a Wednesday.

How many Wednesdays occurred in 2014?

2014 was not a leap year.

ID 4648

Divide 55 into two parts so that one will be 150 percent of the other.

What is the smallest number?

ID 4830

The product of 33 positive integers is 33.

What is the sum of the numbers?

ID 4906

Estimate the product of the digits of the number 7777777.

ID 4921

Find the midpoint between the points one fifth and fifteen.

ID 4959

100 is to 121 as 10 to . . .

ID 5006

Use four 9's and any math signs to make 100.

How many sign '+' did you use?

ID 5378

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.

ID 5422

The ratio of two numbers is 3 : 5.
The difference between the numbers is 8.
What is the sum of the two numbers?

ID 5436

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).

ID 5439

When N copies of the integer N are multiplied together, the product is 256.

What is N?

ID 5644

How many positive integers that are strictly less than one hundred are evenly divisible by both 2 and 3?

ID 5758

39 x 93 =

ID 6034

Find

22 + 20 + 21 + 27

ID 6248

22017 - 22016 = ?

ID 6533

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.

ID 6598

If A, B, and C are different digits, how many different solutions does the number puzzle have?

ID 6725

Spotting patterns is very important.

Can you spot which number doesn't fit the pattern?

1,   2,   5,   14,   42,   122,   . . .

Author: Leslie Green

ID 6976

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?

ID 7028

Which number represents the smallest amount?

ID 7192