answer reg = There is confusion between the language and the correct mathematical notation. In the old system of pounds, shillings and pence all the units were used because it was not a metric system of measurement. In the example you quote, the ".31" is a decimal fraction of a pound, not of the pence. This means that it is incorrect to include both units as this makes a confusion as to which measure is being used.
A similar error occurs when units of time are used, particularly when a calculator is employed in speed distancetime measures. Pupils often read a measure of time such as 3.45 hours as 3 hours and 45 minutes. It should be 3 hours and 27 minutes (0.45 of an hour, or 60 minutes, is thus 0.45 X 60 = 27).
Never feel foolish about asking if you aren't sure about something in maths. We have gaps in our knowledge or misunderstandings which can come from our own learning experience in maths, The longer you have been supporting pupils, particularly having experience with different teachers, the fewer gaps there are. But even teachers have these gaps and a query from you can make us question our own practice or the language we use which might be confusing. Teachers are always honing their knowledge and skills.
How would you introduce a lesson on enlargements?
answer reg = When teaching enlargements I vary my practice depending on the group or the year. To keep it fresh will take new approaches, collecting ideas from colleagues and storing them for future use.
This is one that I have found to be successful. Type in 48-point in blue the word ENLARGEMENT. Then photocopy it using three different sizes bigger and two smaller. I have used 130%, 180%, and 210% , 85%, and 10%. Vary these according to the ability of the group and how much they like a challenge. Mount them on coloured card and write the percentage on the back and stick these to the board or wall prior to the lesson.
When pupils have settled, say, very quietly: "Today we are going to look at enlargements." Then repeat it loudly. Ask if any of them know who John Lennon and Yoko Ono are. Then tell them this TORY:Yoko Ono is an artist.
John Lennon was visiting the Indica Gallery, St James Street in London where Yoko had an exhibition of her art on November 9 1966. He saw a piece of artwork - a stepladder leading to a canvas on the ceiling which had a magnifying glass hanging down from it. He climbed the ladder to look at the miniature writing on the canvas which was not visible without the magnifying glass. The word just said "Yes". Enlargement used in art. (From this time on the two were inseparable and married in 1969.) Then tell them that you have taken the word "enlargement" and changed its size on the photocopier. Ask the class to guess the size of each one - a prize for the most accurate, perhaps. As each is guessed and the correct percentage identified, remove each card until only the original size is left.
Having already indicated the use of enlargements in art, ask the pupils if they can think where enlargements are used in real life. Examples from previous lessons have included photographers, graphic designers in publicity material for different replications of the same poster, microscopes by scientists and doctors, designers and architects for their plans, photocopier, overhead projectors, magnifying glass for jewellers, philatelists, diamond cutters, Maps and cartographers, opticians looking at the eye, model-making, astronomers viewing the planets, restoration work and so on.
Hugh Beere has created a Flash program about enlargements which is available on www.mathagonyaunt.co.uk and linked to this week's article.
This works well on an interactive whiteboard. Other contributions are welcome.
A little poem...
Create a relationship now you can Use enlargement to catch your man!
A stirring of the senses occurred A magnifying glass to read the word Printed on a canvas the word "Yes" For a lesson suggested by TES.
Wendy Fortescue-Hubbard is a teacher and game inventor. She has been awarded a three-year fellowship by the National Endowment for Science, Technology and the Arts (NESTA) www.nesta.org.uk to spread maths to the masses. Email your questions to Mathagony Aunt at firstname.lastname@example.org Or write to TES Teacher, Admiral House, 66-68 East Smithfield, London E1W 1BX