Two guests shake hands exactly once with one another. How many handskakes are exchanged among nine guests ?

There are two paths linking a school to a park. From the park, there are three paths leading to the library. There are four paths from the library to a shopping mall. How many different ways are there to go to the shopping mall from the school ?

A “ Happy Holiday!” greeting was exchanged exactly once between two good friends. How many “ Happy Holiday!” greetings were exchanged among five good friends ?

There are 4 points on the circle below. How many triangles can you draw using any three points ?

How many different ways are there to get a sum of 80 cents from two 50 cents, four 20 cents and eight 10 cents coins ?

How many different ways are there to make up 6 dollars from one 5 dollars note, three 2 dollars notes and six 1 dollar notes ?

Sân bay quốc tế Tân Sơn Nhất ở thành phố nào?

We put 2, 0, 1, 3 into an adding machine, as shown.

What is the result in the box with the question mark ?

Nathalie wanted to build the same cube as Diana had ( see the picture )

Nathalie ran out of small cubes and built only the part of the cube, as you can see in the picture. How many more small cubes did Nathalie need to complete her cube ?

The diagram is a scale respresentation of the distance between Mara’s house and the house of her friend Bunica. One half, one quarter and one eighth of the distance are marked on the diagram

What is the real distance between the two houses ?

Nick is learning to drive on the training ground shown on the figure. He knows how to turn right but cannot turn left. What is the smallest number of turns he must make in order to get from point A to point B, starting in the direction of the arrow ?

The total of the ages of Ann, Bob and Chris is 31 years. What will the total of ages be in three years time ?

The Gurukans have three little daughters. Every daughter has exactly two brothers. How many people are there in the family ?

Michael has to take a pill every 15 minutes. He took the first pill at 11:05. At what time did he take the fourth pill ?

By drawing two circles, Mike obtained a figure, which consists of three regions ( see picture ). At most how many regions could he obtain by drawing two squares ?

The number 36 has the property that it is divisible by the digit in the unit position, because 36 is divisible by 6. The number 38 does not have this property. How many numbers between 20 and 30 have this property ?

The incorrect equality statement 1 + 3 + 6 x 2 = 22 may be made correct by increasing one of the numbers in it by 1. Which number should it be ?

Which of the following pieces covers the largest number of dots in the table ?

Mary shades various shapes on square sheets of paper, as shown.

How many of these shapes have the same perimeter as she sheet of paper itself ?

Ann rides her bicycle throughout the afternoon with constant speed. At the beginning and at the end of the route, her watch shows the time, as in the diagram:

Which picture shows the position of the minute hand when Ann finishes one third of the ride ?

Matthew is catching fish. If he had caught three times as many as he actually did, he would have 12 more. How many fish did he catch ?

How many different squares of any size can you identify in the picture ?

Max, David and Peter completed in an ice cream eating contest. Max ate 6 scoops in the same time as David ate 4 scoops and Peter ate 5 scoops. Max ate 18 scoops in half an hour. How many scoops in total did they eat in half an hour together ?

From a wooden cube with side 3 cm we cut out at the corner a little cube with side 1 cm ( see picture ). What is the number of faces of the solid after cutting out such a small cube at each corner of the big cube ?

How many pairs of two-digit natural numbers have a difference equal to 50 ?