How many Triangles are there in each of the following figures?

Find the number of dots in the tenth figure of the following patterns.

Suppose, you have two shorts, one is black and the other one is blue; three shirts which are in white, blue and red. You again wish to make different combinations, but you always want to make sure that the shorts and shirt that you wear are of different colours. List and check how many combinations are possible now.

How many Triangles are there in each of the following figures?

Arrange the odd numbers from 1 to 17 without repetition to get a sum of 30 on each side of the magic triangle.

(i) Draw the next pattern.
(ii) Prepare a table for the number of dots used for each pattern.
(iii) Explain the pattern.
(iv) Find the number of dots in the 25^th pattern.

Find the minimum number of straight lines used in forming the following figures.