0° C → 0+30 → 30° F (low by 2°) 10° C → 20+30 → 50° F (exact!) 30° C → 60+30 → 90° F (high by 4°) 180° C → 360+30 → 390° F (high by 34°, not good) Examples °F → °C: 40° F → 10/2 → 5° C (almost right) 80° F → 50/2 → 25° C (low by about 2°) 120° F → 90/2 → 45° C (low by about 4°)

30 grados celsius a fahrenheit