In a box of chocolates, there are 11 milk chocolates, 5 dark chocolates, and 7 white chocolates. Charlie takes one of the chocolates at random. Write down the probability that Charlie takes a white chocolate.

Rachel has two bags. In the first bag, there are 4 red balls and 6 green balls. In the second bag, there are 3 red balls and 5 green balls. Rachel takes at random a ball from the first bag. She then takes at random a ball from the second bag. Work out the probability that Rachel takes two green balls.

Here are the first four terms of a sequence:

7, 13, 19, 25

The size of each exterior angle in a regular polygon is 20°. Work out how many sides the polygon has.

Work out ³⁄₄ × ⁵⁄₆.