```calc
F := 2.5 kN
A := 25 mm*40 mm
σ := F/A = ?
```

```calc
v := 90 km/hr
t := 2 s
a := v/t = ?
```

```calc
σ = ? psi
v = ?
E_day := 3 kW*8 hr = ? kW*hr
E_day = ? MJ
```

```calc
x := 3 m + 2 s
```