The formula to calculate the Mach Number (M) is:
\[ M = \frac{u}{c} \]
Where:
Let's say the local velocity (u) is 340 m/s and the speed of sound (c) is 340 m/s. Using the formula:
\[ M = \frac{340}{340} = 1 \]
So, the Mach number is 1.