## Monday, February 7, 2011

### NAPLAN preparation

There are lots of times you are surprised as a teacher. Today I did some NAPLAN revision of decimal numbers with my year 9 class. It really surprised me how difficult students find the concept of decimal numbers.

Here's something to try with your child.

Draw a number line and place 4.5 at one end and 4.6 at the other.

Place a marker in the middle and ask your child what number would go there.

The answer is 4.55 and many students may get this right, but many would not be 100% sure.

Split the number line again so that it is now in four equal sections. Ask your student to label the new sections.

You may get a wide variety of answers and weird looks.

The answer is 4.5, 4.525, 4.55, 4.575 and 4.6

If your child cannot do this they are not alone. Try again using whole numbers and break it into ten equal sections. Try asking for points between intervals.

Errors like these indicate an issue with both division and place value. It can easily be remedied with some place value exercises (to check if they understand that 4.6 is bigger than 4.59), some estimation exercises (to check if their answers are feasible/reasonable), determining how to find the width of set intervals (using division), learning how to add on intervals and how to find midpoints of intervals.