Very often children ask questions like How many stars are there in the sky ? Or, How many hair are there on our head ? Or how many holes are there in a net, say in a mosquito net.
Apparently it looks difficul, if you start counting them, but if you find out the no. of holes in a small area of 1"x1" and then find the total area of the net in inches. Then multiply the two to get the approximate total no of holes in a net!.
Interesting! Isn't it.