# SI Prefixes Used with Units



Below are shown the prefixes (factors) used with units of lengths, mass, area, volume, .... The symbol, the name and the corresponding factor are presented in the table below. Example with each of the 12 symbols are also included. More exercises with solutions are presented at the bottom of the page.

Note several forms of the factors corresponding to the SI prefixes are given: decimal, division, fraction and power to cater for all levels. In the examples below, the calculations are done using the decimal form, however the other forms may also be used.

## Definition of Prefixes

A prefix (in units) is a word that precede a basic unit, such as meter, grams ..., that indicates a multiple ( > 1 ) or fraction ( < 1) of the basic unit.
For example kilometer is made of the prefix kilo (in Greek) which means a thousand and the basic unit meter .

1 kilometer = 1000 meters

The table below shows the names of some of the mostly used prefixes, their abbreviations and the corresponding factor.

## Examples with Solutions

Basic units such as meter (length), liter (volume), gram (mass) and Watt (power) are used in the examples below.

Example 1
Convert $$7 \; \color{red}{\textbf{pico}} \textbf{meters}$$ to meters.

Example 2
Convert $$3.2 \; \color{red}{\textbf{nano}}\textbf{meters}$$ to meters.

Example 3
Convert $$8 \; \color{red}{\textbf{micro}} \textbf{grams}$$ to grams

Example 4
Convert $$0.4 \; \color{red}{\textbf{milli}} \textbf{liters}$$ to liters.

Example 5
Convert $$7 \; \color{red}{\textbf{centi}}\textbf{grams}$$ to grams

Example 6
Convert $$2.01 \; \color{red}{\textbf{deci}}\textbf{meters}$$ to meters.

Example 7
Convert $$5 \; \color{red}{\textbf{deka}}\textbf{meters}$$ to meters.

Example 8
Convert $$9.23 \; \color{red}{\textbf{hecto}}\textbf{liters}$$ to liters.

Example 9
Convert $$3.4 \; \color{red}{\textbf{kilo}}\textbf{grams}$$ to grams.

Example 10
Convert $$7.6 \color{red}{\textbf{ Mega}}\textbf{Watts}$$ to Watts.

Example 11
Convert $$0.3 \; \color{red}{\textbf{Giga}}\textbf{Watts}$$ to Watts.

Example 12
Convert $$1.3 \; \color{red}{\textbf{Tera}}\textbf{Watts}$$ to Watts.

## Exercises

Part A

Identify the prefix used and convert to meters (m).

1. $$\quad 0.02 \text { Mm}$$
2. $$\quad 234 \text { dam}$$
3. $$\quad 1200 \text { pm}$$
4. $$\quad 205 \text { nm}$$
5. $$\quad 0.002 \text { cm}$$
6. $$\quad 1.002 \text { hm}$$
7. $$\quad 0.005 \text { Gm}$$
8. $$\quad 1.34 \; \mu \text{m}$$
9. $$\quad 23000 \; \text{mm}$$
10. $$\quad 1.003 \; \text{dm}$$
11. $$\quad 0.02 \; \text{km}$$
12. $$\quad 0.01 \text { Tm}$$

Part B

Identify the prefix used and convert to grams (g).

1. $$\quad 0.003 \text { Tg}$$
2. $$\quad 0.3 \; \text{dg}$$
3. $$\quad 1.2 \; \text{kg}$$
4. $$\quad 1000 \; \mu \text{g}$$
5. $$\quad 0.056 \text { Mg}$$
6. $$\quad 2.3 \text { dag}$$
7. $$\quad 102.4 \text { cg}$$
8. $$\quad 20.2 \text { hg}$$
9. $$\quad 0.001 \text { Gg}$$
10. $$\quad 1100 \text { pg}$$
11. $$\quad 9000 \text { ng}$$
12. $$\quad 23000 \; \text{mg}$$

Part C

Identify the prefix used and convert to litters (L).

1. $$\quad 200 \; \text{mL}$$
2. $$\quad 0.005 \text { TL}$$
3. $$\quad 1.4 \text { hL}$$
4. $$\quad 0.00002 \text { GL}$$
5. $$\quad 440000 \text { pL}$$
6. $$\quad 500 \text { nL}$$
7. $$\quad 0.007 \text { ML}$$
8. $$\quad 1.06 \text { daL}$$
9. $$\quad 203.6 \text { cL}$$
10. $$\quad 0.02\; \text{dL}$$
11. $$\quad 10.1 \; \text{kL}$$
12. $$\quad 100 \; \mu \text{L}$$