Tag Archives: rounding

282. Round the Venn

My next class neighbour, Mr D, has been evangelising about venn diagrams since he did the TAM (Teach A-level Mathematics) course. His lesson on equations and graphs using venn diagrams was brilliant! Then, at MathsConf5, Craig Barton (@mrbartonmaths) shared his love of venn diagrams.

And they are on the new english GCSE Maths syllabus.

In light of all this, I introduced venn diagrams as a vehicle for probability (Y10) and rounding (Y9).

Introduction

First of all I used the films of Tim Burton, Johnny Depp and Helena Bonham-Carter to introduce a triple venn diagram, with the box to represent everything – I like dropping in the proper forms or technical bits early on in all topics.

image

We had quite a lengthy conversation about films, including why the Bond film could be on the diagram. The discreet use of IMDB (with my permission) settled some arguments too!

Rounding

I wanted my Year 9s to consider the differences and similarities between different forms of rounding. I created a simple diagram for them to complete where they compare ‘nearest ten, ‘one decimal place’ and ‘two significant figures’. You can download it here:

Rounding Venn Diagram worksheet

Probability

For my probability lesson I used the probability PowerPoint by Craig Barton. You can link to his resources here:

Mr Barton’s venn diagram resources

158. May I take your order, sir?

Imagine getting your class to think about a number topic in a real-life context and subsequently having students leave the lesson feeling happy they could use this skill.

About as real as the square root of minus one? Not if you relate it to breakfast*

Image credit: ifood.tv

I wanted to make estimation more relevant for my class, a low ability Year 10. Outside my classroom I put a breakfast menu and my associate teacher took their orders** as they entered the classroom. I had put mini whiteboards on tables and I instructed the class to work out an estimate and the accurate total for their menu choice(s). The lesson had barely begun and the class were already talking about what they were doing (rather than Halloween antics the night before)!

Once everyone had arrived and settled down, I asked if anyone had underestimated and what this would mean – not enough money and doing the washing up!

I then asked each table how much their group order would cost. Would their overestimates cancel out their underestimates? Would the waiter get a tip? Meanwhile the associate teacher had added up the orders, so we could quickly check their calculations.

What if everyone paid £10? Would you have enough? How much tip would you be leaving? Would it cover a 10% service charge?

We followed up this task with some standard estimating questions.

Image credit: www.fudds.ca

The menus I used for the lesson are from a restaurant chain in California. The useful thing is there are no units of currency, so this works for different countries. It will work equally well with KS2 and KS3 pupils.

Download resource: Breakfast estimation (pdf)

BTW The students decided if the waiter wanted a tip, he should actually feed them first!

*Strongly suggest you use this before students have break or lunch time, or else they’ll be drooling in their next lesson.

**Unless you are providing food, please add the disclaimer that you are not feeding them.