Record income from logs this year


Two opportunities for tapping numeracy skills exist in this article and they could be combined with a social science or science study of forestry in Tasmania (or another state). The opportunities relate to percentage and the measurement of volume.

In the second paragraph we find that a 40% higher royalty was received this year over the previous year, amounting to $240,000. The natural question to ask is, given this information what was the total royalty received this year? [There are several ways of conceiving this problem in terms of ratio and percentage. Perhaps the most intuitive is to think of last years' royalty as X; then 40% of X is $240,000. In decimal form 0.4 X = $240,000 or X = $600,000 was last year's royalty. This year's is hence $600,000 + $240,000 = $840,000.] Students should be encouraged to develop different strategies and share them with each other.

In the last paragraph we see that more than 240,000 cubic metres of logs have been sold since 1992. How easy is it to imagine 240,000 cubic metres of logs? This volume could be associated with a very large cube but how long would this cube be on each side? Students often have difficulty with the cubic relationship between the side of a cube in linear metres and the volume inside in cubic metres. Ask students to estimate how long the cube would be on each edge. Depending on the availability of a calculator which can calculate cube roots, this exercise could be long or short. If students estimate the length of an edge, these values can be checked by multiplication on any calculator to see how close to 240,000 cubic metres they can get. This is a very good exercise in estimating and checking and usually first guesses will be much too large. It turns out that the length of an edge is about 62 metres. It is possible to measure out on a large playground or along a footpath near the school this length. It may be possible in some circumstances to measure a square 62 metres on each side and discuss how many square metres are in it. Then total imagination will be required to imagine this square piled 62 metres high with logs! Students might, however, like to draw and label their conceptualisation of this volume of logs.


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