Ruler

Introduction

This section will help you correctly read all metric rulers including the 'four fold ruler'. The four fold ruler is used by many builders. When fully extended it has a total length of 1 metre.

For the following questions select your answer to receive feedback.

Photo of a four fold ruler.

Question 1

The ruler length is 1 metre, what is this in millimetres?

Photo of a four fold ruler.

Question 2

If the four fold ruler has a total length of 1 metre, how long is each of the four sections of the ruler?

Reading the ruler

The smallest markings on a metric ruler are set 1 mm apart. Numbers are only written every 10 millimetres. Numbers every 10 millimetres helps you count and read a measurement on the ruler.

Photo of the markings on a four fold ruler.

Reading the ruler

What is the distance from the left hand end of the ruler to the arrow?

Photo a four fold ruler with an arrow pointing to the third division on the scale after the number 20.

Reading a ruler

Photo a four fold ruler with an arrow pointing to zero, a second arrow pointing to 20 and a larger arrow pointing to the third division after 20.

The distance from the left hand end of the ruler to the black arrow is 23 mm.

Here's how to work it out:

The left hand end of the ruler is 0 (first red arrow).
From zero look across and read the last number before the black arrow
– this number is 20 (second red arrow).
Count the number of divisions between 20 and the black arrow – there are 3.
Add the two numbers together.
20 + 3 = 23 mm.

Question 3 – Reading the ruler

Photo a four fold ruler with an arrow pointing to fifth division after the 100 and then the 10 on the scale.

Write the value marked on the ruler into the box and select submit.

mm Submit

Reading a ruler

Photo a four fold ruler with arrows pointing to zero, 100 and the 10 after 100. There is a larger arrow pointing to the fifth division after the third arrow.

Here's how this measurement is determined.

Between the left end of the ruler and the black arrow is one 100 mark (second red arrow)
– 1 x 100 = 100 mm.
Read the last number between the 100 mark and the black arrow (third red arrow)
– this equals 10 mm.
Count the divisions from 10 to the black arrow
– this is 5 mm.
Add the three numbers together.
100 + 10 + 5 = 115 mm.

Photo a four fold ruler with an arrow pointing to the second division after the 60 on the scale.

Question 4 – Reading the ruler

Write the value marked on the ruler into the box and select submit.

mm Submit

Using the four fold ruler

Watch how a builder uses a four fold ruler to take a measurement.

Select the play button to begin.

Text version

Now it’s your turn to take some measurements. Download and print the document Estimating and measuring (Word 245kb). Follow the steps in the document. When you have finished show your results to your teacher.

Summary

This is the end of the section on reading a four fold ruler.

Key points to remember are:

the smallest division on the ruler = 1 mm
numbers are only written on the ruler every 10 mm.

You can review this section or choose another from the left hand menu.