He can build ...
... min(floor((available wood)/(wood per chair)), floor((available glue)/(glue per chair)))
... = min(floor(6/4), floor(12/6))
... = min(1, 2) = 1
The carpenter can build ...
... e. one chair
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The floor( ) function returns the largest integer not greater than its argument. That is, the value with the fractional part set to zero (for positive numbers).