Professor Layton and the Unwound Future is a puzzle game for the Nintendo DS.
Puzzle number 40 is this :
The description is a bit unclear. What they seem to want is :
a * b = c + d
and
a + b = c * d
Plugging this in Wolfram Alpha as :
((a + b ) = (c * d)) and ((a * b) = (c + d)) and (a > 0) and (a < 10)