This week I’ve been working with secondary TAs and fractions and we were considering the calculation
We explore different strategies and then showed them a number line, counting on from the part to the whole, they really weren’t happy.
I then shared 2003-1998. They instantly related this it to something familiar: “Oh, that’s like counting back years.” They said they would count on and potentially model using a numberline.
My next example was 4002 – 3995 – again the numberline was the most appropriate method for them.
Why were they happy with integers and not fractions? When I put the two fractions on the numberline, they didn’t see it as the same number line they used for whole numbers. It felt like a new representation, not a continuation of the one they knew. They were not familiar with fractions as points on a line nor fractions as a distance.
To make number lines feel natural for fractions, learners need to see:
- mixed numbers placed accurately
- fractional intervals marked clearly
- jumps shown visually
- the connection to integer number lines made more explicit
Do I model the use of numberlines to for subtraction of mixed numbers enough?
Vanessa Brown - Truly Inspirational Maths 