**Multiples and Sub Multiples**

Being able to convert between an SI base unit and its multiples and sub multiples is an essential skill for the IMAT and will be of great use to you in almost all the sections of the IMAT, not just physics.

Make sure you can remember the following…

**SI Derived Units**

The above SI units are essential for almost all sections in the IMAT; however, the SI derived units are only relevant for physics. Nevertheless, questions on SI derived units are not uncommon in the IMAT and are thus worth learning.

The following derived units are worth putting to memory…

**Converting Area **

When converting between say square meters and square centimeters, you may be tempted to think that 1m = 100cm and thus that the area in square centimeters is just 100 times as much as the area in square meters. This is NOT how it works

To convert between areas is simple, just move with a factor of 100 for each multiple or submultiple

- When going down multiply by a factor(s) of 100: i.e., 1 m
^{2}= 100 dm^{2} - When going up divide by a factor(s) of 100: i.e., 1 m
^{2}= 0.01 dam^{2}

The movement between one multiple or submultiple to the next will involve one factor of 100. Moving from for instance meters to centimeters is moving down TWO submultiples thus you will need to multiply by TWO factors of 100 (that is 10,000).

**Converting Volumes**

The exact same logic applies, but here we are moving by a factor(s) of 1000 instead.