Query Builder, select multiplication of two columns?

I have a simple SELECT statement I am trying to put into query builder.

SELECT sc.term * ss.intervals AS count

Works fine as a SELECT statement

I try to put it in a query builder select like so:

->select('sc.term * ss.intervals AS count')

It gives a syntax error because it converts to this:

SELECT `sc`.`term` AS `* ss`.`intervals AS count`

What is the proper way to select a multiplication like this in query builder?