Answer :
To convert a temperature from Fahrenheit to Celsius, you use the formula
$$
C = \frac{5}{9}(F - 32).
$$
Barbara starts with $F = 78^\circ F$. The first step is to subtract 32 from 78:
$$
78 - 32 = 46.
$$
The next step is to multiply the result, 46, by $\frac{5}{9}$:
$$
46 \times \frac{5}{9}.
$$
This multiplication gives the temperature in degrees Celsius. Therefore, the next step is to multiply 46 by $\frac{5}{9}$.
$$
C = \frac{5}{9}(F - 32).
$$
Barbara starts with $F = 78^\circ F$. The first step is to subtract 32 from 78:
$$
78 - 32 = 46.
$$
The next step is to multiply the result, 46, by $\frac{5}{9}$:
$$
46 \times \frac{5}{9}.
$$
This multiplication gives the temperature in degrees Celsius. Therefore, the next step is to multiply 46 by $\frac{5}{9}$.