Place value rears its ugly head again.

As I suspected, Place Value became a noticeable issue again when trying to teach how to use Place Value as a subtraction strategy in week 3 of term 2.

This time, I took a different strategy with the stick counting method. I assigned each colour a particular value coinciding with the different place values from ones to 100 000s. Learners used the valued sticks to create numbers and solve increasingly difficult subtraction problems. See the task here.

Assigning sticks a different value per colour is an adaptation of an idea gained from my study of the Ancient Egyptian and Chinese Number Systems compared to other number systems including the modern Place Value system. The idea being that the colours provide a visual cue for the worth of each place value as the Chinese characters and Egyptian hieroglyphs do.

Keeping numbers organised in their discrete place values also forces the user to exchange sticks for usable sticks when subtracting beyond the means of the value being subtracted. For example when doing the subtraction 12 - 7, seven ones can't be taken from 2 ones, thus forcing the ten to be exchanged for 10 ones. Incidentally, discussing these place values, subtraction, exchanging, and breaking etc. exposes learners to the vocabulary needed to truly understand the written algorithm.

The lessons were successful with most, if not all, learners picking up enough understanding of Place Value to use it as a strategy for addition and subtraction from 3 or 4 digit numbers and higher. One of the two learners that did not pick it up to the 3 digit level is noted for their absence and lack of engagement in school.