📖Definition
Depending on what's being measured, some units are more suitable than others.
For example, if you're weighing a mouse, grams are the best unit.
But if you're weighing a dog, kg are more suitable.
You may be asked to compare quantities given in different units. To save time in the exam, you need to be able to convert easily between different units in the metric system.
Here are some equivalents that you should know.
Diagram
You might also be asked to convert between metric and imperial units or vice versa. For this, you will be told the metric/imperial equivalent. Look at the worked example to see this in practice.
💡Tips/hints
Learn all the units and equivalents so you can use them without thinking.
✏️Example
1 inch = 2.5cm. A piece of wood is 16 inches long. What is its length in cm?
✅Solution
If 1 inch = 2.5cm, then 16 inches = 16 x 2.5 cm = 40cm.
✏️Example
Which of these is the longest distance?
2821m, 28190cm, 2.9km, 290000mm
✅Solution
Let's look at the m and km first.
1000m = 1km so, 2821m = 2.821km
So, 2.9km is larger.
Now let's look at the cm and mm.
10mm = 1cm so, 290000mm = 29000cm
which is larger than 28190cm.
So, we need to compare 29000cm and 2.9km.
Let's convert both to metres.
100cm = 1m so 29000cm = 290m.
1km = 1000m so 2.9km = 2900m so 2.9km is the largest.