The Math functions action allows you to do math on values.
Although you cannot group different operations together, you can chain the same operation. In other words, you can't add two numbers and then multiply it by another number in the same function, but you can add as many numbers as you like together.
The operations available are:
Add
Subtract
Multiply
Divide
Max: Given two or more numbers, return the largest number
Min: Given two or more numbers, return the smallest number
Power
DivRem: Remainder after division (modulo operation)
Percentage: Return the percentage of a given amount
Round
Absolute Value
Square Root
Sin
Cos
Tan
Log
Log10