6 - 7 year olds

Look at these figures.

They have been traced by blue strings in a big grid. In each point of the grid in which the string goes by we have placed an orange button, In those points that are inside the figure we have placed green buttons. Sometimes the figures that we do are more complicated, with some holes. Here is an example in which the hole is shown in yellow. The orange buttons we will say that are located in the BORDER of the figure. The green buttons we will say that they are located in the INSIDE of the figure.

a) How many buttons are there in the border and how many inside the next two figures?

b) Here we show you another figure. The empty surface (in yellow) is not part of the inside of the figure. Please find the exact number of buttons on its border and the amount in the inside.

c) In this grid, you need to draw a figure that has no interior buttons but has at least 23 buttons on the border.