# Averages and Range Spiders: TES Maths Resource of the Week

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What is it?
For me, 2017 has been the year of the spider! I have already featured a spider activity as one of my previous Resource of the Week selections, but when I saw the quality of this resource, I could not resist choosing one again. This particular spider tackles the topic of averages and range in an incredibly challenging, engaging and ultimately useful way. Given a set of 5 numbers, one of which is missing, students must choose a correct number to match a series of conditions related to average and range, such as making the median 4, or the range 6. This gets them thinking about averages in reverse, and can lead to a deeper understanding of a topic that is often in danger of being dominated by abstract, easily forgotten rules.

How can it be used?
If students are not comfortable with the basics, then an activity like this may well tip them over the edge! So, I would advise covering or recapping the concepts of mean, median, mode and range first. Then, when you feel students are ready for the challenge, it is time to unleash the spider! This activity lends itself well to paired work, providing plenty of opportunity for discussion, especially on those occasions when there might be more than one correct answer. The third spider even introduces two missing numbers, which significantly ups the challenge. Fortunately, answers are provided. Finally, there is always the opportunity to ask students to create their own spiders, maybe with constraints that they cannot have the same answer more than once, to really test their understanding.

Thanks so much for sharing
Craig Barton