Thursday, April 9, 2009

Division of Fractions

I have just completed nine periods of mathematics lesson on this unit with a class of primary five students who struggle with mathematics. I am teaching dividing fraction a/b by a whole number c which is often done using the invert-and-multiply method. Instead of using this method which I believe contribute to these students' difficulties with mathematics, I use an alternate method which based on simple reasoning ... if 4 divided by 4 is 1 then 4 fifths divided by 4 is 1 fifth. In cases when this is not obvious such as 2/3 divided by 4 we talked about changing 2/3 into 4/6. 4 sixths divided by 6 was then "easy beezy" as one student put it. It gave the students plenty of chance to revise equivalent fraction, which is fundamental to operations involving fractions.
I particularly enjoyed the third lesson when I gave each pair of students a fraction. If they thought that their fraction has the same value as the one I put up, they put it next to mine. In other words the board was filled with equivalent fractions which the students can then use to do various division.