The figure illustrates a staircase which has 2 steps.
A staircase that Nick and Mike are playing has 21 steps. They count the steps; one from bottom to top and the other from top to bottom. They meet at one step which Nick indicates as the 10th. As which number does Mike indicate this step?
In the box are seven blocks. It is possible to slide the blocks around so that another block can be added to the box. What is the minimum number of blocks that must be moved?
Lines are drawn on a piece of paper and some of the lines are given numbers. The paper is cut along some of these lines and then folded as shown in the picture. Along which lines were the cuts made?
Benjamin chooses a number, divides it by 7, adds 7 to the result and multiplies that result with 7. He obtains the number 777. Which number did he start with?
The numbers 1, 4, 7, 10 and 13 should be written into the squares so that the sum of the three numbers in the horizontal row is equal to the sum of the three numbers in the vertical column. What is the largest possible value of these sums?
In order to produce a newspaper with 60 pages, you need 15 sheets that are bound together. In one such newspaper, page 7 is missing. Which other pages are also missing from this newspaper?
Lydia draws flowers with 5 petals. She wants to colour each petal in either white or black. How many different flowers can she draw this way? (A flower can be totally white or totally black. Two flowers which differ by a rotation are consider the same.)
Three identical dice are glued together as shown. The sum of dots on two opposite sides of a die is always 7. What is the sum of dots on the sides which are glued together?