| Exa 1018 |
| Peta 1015 |
| Tera 1012 |
| Giga 109 |
| Mega 106 |
| Kilo 103 |
| Hecto 102 |
| Deka 10 |
| Deci 10-1 |
| Centi 10-2 |
| Milli 10-3 |
| Micro 10-6 |
| Nano 10-9 |
| Pico 10-12 |
| Femto 10-15 |
| Atto 10-18 |
So: 1000 grams = 1 X 103 = 1000 or 1 kilo
1000 kilos = 1 metric tonne = 1 X 106 = megagram
1 million tonnes = 1 X 109 = 1,000,000,000 grams = 1 gigagram
1 petagram = 1 X 1015 = 1,000,000,000,000,000 = 1 trillion grams = 1 billion metric tonnes