Using the Number Line to Extend Thinking Strategies to Two-Digit Numbers and Beyond
When it comes to calculating with larger numbers mentally, it becomes hard to visualize the amounts, as we must think of quantity images of all the tens and ones we had, and then how many we are adding on. At this point it’s much more helpful to think of a number line beginning at a specific point, and then jumping by tens and by ones.
There is much research showing that the brain actually thinks of the larger units first; that is, if you would ask a student to solve two-digit addition before he or she was taught a formal process for such equations, the child would think of the tens first! The algorithm actually asks us to work against our understanding of numbers! So its crucial to first develop number sense and the ability to calculate mentally, and then to transfer it to the algorithm – the formal paper and pencil process.
There is much research showing that the brain actually thinks of the larger units first; that is, if you would ask a student to solve two-digit addition before he or she was taught a formal process for such equations, the child would think of the tens first! The algorithm actually asks us to work against our understanding of numbers! So its crucial to first develop number sense and the ability to calculate mentally, and then to transfer it to the algorithm – the formal paper and pencil process.
