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Unit: Making measurements

Supporting: MSAPMOPS101A Make measurements

Section 1: Calculating

Using tallies

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Tallies are used to record quantities of particular items or products.

For instance, if you wanted to write down how many power tools you had taken onto a jobsite, your tally might read:

1 x jigsaw; 1 x circular saw; 3 x cordless drills; 2 x claw hammers ...

and so on.

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But if you had a product that was already expressed in terms of its cross-section size, such as 70 x 45 timber, it would get very confusing if you started to use the 'x' ('times') sign to also indicate the number and length of the pieces.

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Set out below are some examples of how to record tallies when you're working with items that are referred to by their cross sectional dimensions.

Note that in most instances, the size of a piece generally refers to its cross section, and the length refers to its lengthwise run.

It's also common practice to express size in millimetres and length in metres.

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Example 1: timber boards

Let's say you have 15 pieces of radiata pine, all 140 mm x 19 mm in size, and there are 5 pieces at 2.4 metres in length, 7 at 2.7 and 3 at 3.6. To write this up as a tally, you should record it as shown in the image.

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Now let's say we wanted to know how many lineal metres this tally represents.

Note that 'lineal' means 'in a line' - so to put the question another way: What is the total metreage of this timber stock if the boards were all laid out in a line?

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The easiest way to find the answer is to use a calculator with a memory button. Although not all calculators work in exactly the same way, the sequence of numbers and function buttons would be similar to that shown in the image.

To see this process written out in more detail, click on the link below.

Detailed description of calculation

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If you don't have a calculator with a memory button, you can simply multiply each line separately and then add the subtotals together, as shown in this image.

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Example 2: steel angle

In this example, we've got two different sizes of material, which means we'll need two separate tallies.

The way you would write up these tallies is shown in the image. What they mean is:

25 mm x 25 mm x 3 mm thick galvanised angle: 1 piece at 6.0 m long and 1 at 7.2 m long 50 mm x 50 mm x 6 mm thick: 2 at 3.0 m and 2 at 4.2 m.

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Example 3: plywood sheets

Sheet materials sometimes have their dimensions shown in metres and sometimes in millimetres.

For example, if you had two sheets of ply that were 18 mm thick, 2.4 metres long and 1.2 metres wide, it could be written up as:

      18 mm ply: 2 / 2.4 x 1.2

or alternatively

      18 mm ply: 2 / 2400 x 1200

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Learning activity

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How many lineal metres (l/m) are in the following bundle of steel rods? Enter your answer into the cell, and click on the 'Check your answer' button to see if you were right.

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13 mm dia. steel rod: 5/4.2, 3/4.8, 2/6.0 47.4lineal metres