A merchant has a 40 kg weight which he used in his shop. Once, it fell from his hands and was broken into 4 pieces. But surprisingly, now he can weigh any weight between 1 kg to 40 kg with the combination of these 4 pieces.

So question is, what are weights of those 4 pieces..?

1+3+9+27=40 9-3+1=5 9-3=6 9+1-3=7 9-1=8 9+3-1=11 27-9-3-1=14 etc etc

When rolling 10 dice with 2020 faces each (numbered 1 to 20), how many ways are there of rolling a total sum of 15?

In how many ways the corners of a square be colored using four colors? 1. If repeat of the colors is allowed. 2. If repeat of the colors is not allowed.

If you have sticks which measure 1, 2, 3, 4, 5, 6, 7, 8 and 9 cm (one of each). How many different triangles can you make using three of the sticks?