# Unit conversion - practice problems

The International System of Units (SI) is the standard system of units used in most countries around the world. It is based on seven base units: the meter for length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the mole for amount of substance, and the candela for luminous intensity. These units can be converted to other units using conversion factors, such as the relationship between meters and centimeters (1 meter = 100 centimeters). Other common SI unit conversions include:

1 liter = 1000 milliliters
1 gram = 1000 milligrams
1 joule = 1 watt-second
1 newton = 1 kilogram-meter per second squared

In the SI system, units can be multiplied or divided by powers of ten to create larger or smaller units. These multiples are called prefixes. The most common prefixes and their meanings are:

mega- (M) = 1,000,000 (e.g. 1 megahertz = 1,000,000 hertz)
kilo- (k) = 1000 (e.g. 1 kilogram = 1000 grams)
centi- (c) = 0.01 (e.g. 1 centimeter = 0.01 meters)
milli- (m) = 0.001 (e.g. 1 milliliter = 0.001 liters)
micro- (µ) = 0.000001 (e.g. 1 microgram = 0.000001 grams)
nano- (n) = 0.000000001 (e.g. 1 nanosecond = 0.000000001 seconds)

It is important to note that, when using these prefixes, the prefix should be written before the unit symbol.

#### Number of problems found: 2126

Do you have homework that you need help solving? Ask a question, and we will try to solve it.

We will send a solution to your e-mail address. Solved problems are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active math competitions such as Mathematical Olympiad, correspondence seminars etc...