Metric units

Units of length Units of mass
1 km = 1000 m 1 tonne = 1000 kg
1 m = 100 cm 1 kg = 1000 g
1 cm = 10 mm 1 g = 1000 mg

Example videos

Video: https://www.youtube.com/embed/ePKBPpHroc8

Video: https://www.youtube.com/embed/8s8g6YUITe4

Video: https://www.youtube.com/embed/alsiTwdLRSY

Imperial units

Units of length Units of mass
1 foot (ft) = 12 inches (in) 16 ounces (oz) = 1 pound (lb)
3 feet = 1 yard (yd) 14 pounds = 1 stone (st)
1760 yards = 1 mile 112 pounds = 1 hundredweight (cwt)
20 hundredweight = 2240 pounds = 1 ton

Example videos

Video: https://www.youtube.com/embed/WVQYWrHhfds

Video: https://www.youtube.com/embed/_qaLMXsVoeE

Converting between metric and imperial units

Rough equivalence between metric and imperial units
1 kg ≈ 2.2 lb (or use 2 lb for a rougher estimate)
1 tonne ≈ 1 ton
1 metre ≈ 39 inches ( or use 1 m ≈ 1 yard for a rougher estimate)
1 km ≈ \( \frac{5}{8} \) mile, or 1 mile ≈ 1.6 km

Example video

Video: https://www.youtube.com/embed/uC9AgTMnpQo