Two-way tables can be used to display information relating to several different options and categories.

The following table shows the number of right and left-handed children in a school year group of 70 children.

Notice how the totals add up in both directions.

There are 56 right-handed children.

There are 32 right-handed girls.

The probability that a child chosen at random is a right-handed girl is 32/70 = 16/35

Always remember to check that you have put the fraction into its simplest form.

Does that all make sense?  Then, let's get started.