1 Using metric measurements

So what do you use to measure things? If you were to measure something small, such as a grain of rice, you would probably use a ruler. To measure something bigger, like the length of a room or garden, you would probably use a tape measure.

You could try estimating the size of something before measuring it, which would help you to decide what tool you need to measure it. If you wanted to measure the walls of a room before redecorating, you’d get a more accurate measurement using a tape measure rather than a 30-centimetre ruler! After you’ve made an estimate you can check how accurate it is by measuring the object.

How long is a pen? Find a pen, make an estimate of how long you think it is and then measure it accurately using a ruler. To measure accurately, line up one end of the pen with the 0 mark on the ruler. If there is no 0 mark, use the end of the ruler. Hold the ruler straight against the pen. Which mark does the other end come to?

Figure 1 Measuring a pen

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An illustration of a pen held against a ruler. One end of the pen is level with 0 cm on the scale; the other end is level with 15 cm on the scale.

Figure 1 Measuring a pen

You can see from this diagram that the pen is 15 cm long.

Now try the following activity. Remember to check your answers once you have completed the questions.