The advantages of the SI (International System of Units) are as follows:

• Rational system: The SI system assigns only one unit to a particular physical quantity, making it a rational system of units. This means that it is easy to remember and use, and there is no need to convert between different units of measurement.

• Coherent system: The SI system is a coherent system of units, which means that it is based on a certain set of fundamental units. This makes it easy to understand and use, and it ensures that all derived units are consistent with the base units.

• Metric system: The SI system is a metric system, which means that multiples and sub-multiples of the system can be expressed as a power of ten. This makes it easy to convert between different units of measurement.

• Internationally accepted: The SI system is the modernized and improved form of the MKS (meter-kilogram-second) system, and it is readily accepted in almost all the countries of the world. This makes it easy to communicate and exchange information across different countries and cultures.

• Versatile and extensive: The SI system offers many benefits, such as being versatile, extensive, complete, and repeatable. It provides several ways to measure both large and small quantities and can be combined to produce more complex units.

• No conversions: The greatest advantage of the SI system is that it has only one unit for each quantity, which means that it is never necessary to convert from one unit to another (within the system) and there are no conversion factors for students to memorize. This makes it easy to learn and use.

• Easy to write and say: Quantities are much easier to express in SI than in other units. For example, 500 watts (500 W) is much simpler than the many confusing, equivalent, non-SI expressions of power such as 1700 British thermal units per hour (1700 Btu/h), 10 300 large calories per day (10 300 Cal/d), 120 thermochemical calories per second (120 calth/s), 22 000 pound (force)-feet per minute (22 000 lbf⋅ft/min), or 0.142 commercial refrigeration tons.

In summary, the SI system is a rational, coherent, metric, and internationally accepted system of units that offers many advantages, such as being versatile, extensive, complete, and repeatable. It is easy to learn and use, and it provides a standard base for measuring any physical property, making it an essential tool for scientists, engineers, and others who need to make accurate measurements.