Volume flow rate is Q = A * v, the cross-sectional area times the average speed through it, tracking how much fluid passes a section each second. The arithmetic is exact only for stated area and speed in the steady incompressible flow model. Real fluids add viscosity, turbulence, compressibility, pipe losses, geometry tolerance, calibration, and measurement uncertainty.
A steady flow rate is checked as area multiplied by speed. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Flow rate is area times speed
Area 2 square metres and speed 3 metres per second give flow 6 cubic metres per second.
Q=2×3=6
The flow label is source-bound
The flow value 6 comes from the displayed area and speed sources.