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
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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.