Multiplication magic square

Weekly Problem 32 - 2015
Can you work out the missing numbers in this multiplication magic square?
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

Problem



Image
Multiplication Magic Square


In this Multiplication Magic Square, the product of the three numbers in each row, column and diagonal is $1$.

What is the value of $r+s$?

If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.