Answer
The numerical value in $^{\circ}F$ matches numerical value in $^{\circ}C$ when the temperature is $-40^{\circ}F$ (which is equal to $-40^{\circ}C$)
Work Step by Step
We can use the equation to convert from Fahrenheit to Celsius to solve for F when C = F.
$C = \frac{5}{9}(F-32)$
$F = \frac{5}{9}(F-32)$
$9F = 5F-160$
$4F = -160$
$F = -40$
The numerical value in $^{\circ}F$ matches numerical value in $^{\circ}C$ when the temperature is $-40^{\circ}F$ (which is equal to $-40^{\circ}C$).
