TDD Practice - Divide without Divide

One question I use to coach test driven development with team members who are new to the concept is:

Write a function to divide without using the / operator.

It’s a great exercise, to break habits because / is a fundamental function that it’s implemented at the CPU level - one will have to work to avoid using it.

Given this criteria and the following test:

it 'divides by 1' do
  divide(1,1).to eq(1)
end

What would you write?

def divide(a,b)
   # what would you write here?
end

Think about this and implement it yourself before moving forward.