Step 1: Tap Start Voice to perform mathematical function.
To perform addition(+) use word "plus". For e.g speak "Five plus three".
To perform substraction(-) use word "minus". For e.g speak "Thirteen minus ten".
To perform multiplication(*) use word "multiplied by". For e.g speak "Seven multiplied by ten".
To perform division(/) use word "divided by". For e.g speak "Twenty-five divided by five".