Estimation as Self-Assessment

There are days when I feel like such a learner in math.  Sure, I feel confident in how I have students learn math concepts.  As teachers we try to keep learning as ‘real world’ as possible.  However, in the last decade the approaches to math instruction have changed so much that it seems we are re-learning this core subject regularly.

I really like that math is more visual now.  But while introducing kids to multiple ways to solve problems beyond the ‘traditional’ methods parents understand it sometimes seems like multiple methods can complicate the learning for some students who aren’t confident in their math abilities.

Often I wonder how powerful the ideas of open number lines, part/part/whole maps, math talks (decomposition, place value) and algorithms would be if I wasn’t the one (in grade 4) to be introducing strategies as a brand new idea. At this point there is not consistency in their usage from one teacher to the next so it seems like a lot of teaching and modelling the strategy vs. simply continuing the successful application of the strategy.  But this is a turning point and as teachers we are learning about the power of these ‘new’ ways to teach math. We are learners, too.  It’s a turn in the right direction.

Estimation is my secret weapon this year.  A student who quickly estimates an answer before selecting a calculation strategy is truly a math thinker. When approaching a problem I first want students to step back and figure out what is being asked of them (for example, how would the problem be represented in a part / part / whole map?).  It means that students are figuring out the WHAT   before getting lost in the HOW.  Having an estimated answer allows students to self-assess and confirm or revise the thinking around their actual calculations.

Think about the estimating we do as adults in the real world.  We are mentally rounding and adding or subtracting multiple numbers regularly.  When a total at the till doesn’t match what we thought it should be, we immediately question the total (or cashier).  It means something went ‘clunk’. That’s a great thing because it means we are actively doing math mentally.  It helps us keep things in check.

I’m a learner too, but if a classroom strategy connects with a real-world need, I think it validates my approach.