Think Math Grade 3 for parents
Parents like to know that the program has a full range of mathematics (i.e., geometry as well as arithmetic), but really does a good job on building competence in addition, subtraction, multiplication, and making the “rules” of those make sense. With at least some of these, let the parents try, themselves, after you’ve given just enough context so that the visual and the idea aren’t mysterious.
Careful development of multi-digit addition and subtraction, and the algorithm
An image of where numbers lie between other numbers (rounding up or down to nearest 10…), and using that to help find the distance between two numbers (mental subtraction. Children think of nearby multiples of 10 to help. In the first problem, they might sketch (without worrying about precision) where 20 belongs, and maybe even where 30 belongs, and then think “the distance between 19 and 35 is” and look at the distance from 19 to 20 (one step), the distance from there to 30 (ten more steps) and the remaining distance (five more) for a total of 16 steps.
With practice, this becomes possible to think about mentally. The distance from 19 to 51 is, um, 1 plus 30 plus 1. This is the way cashiers used to think about making change by adding rather than subtracting.
Estimation to understand what “carrying”is about
The same question, but written in a form that anticipates the “standard algorithm.”
Another step, dealing with hundreds. Again, estimation and then the written form.
Putting it all together,starting with a rough estimate, then getting more precise.
Another view, giving visual images to the addition of ones, tens, and hundreds.
This is done also with the blocks that these sketches symbolize.
One more step to independence. Same view, but only with numbers.
We take the same careful approach in subtraction.Try to do these problems in exactly the way they are suggested, first estimating the hundreds, then the tens…
Finally a quick (very partial) look at multiplication.(Much more is done to complete the process of multiplying two-digit numbers.)
The first picture shows why 47 = 74. The number of dimes is the same no matter which way we look at that array. It also shows how to think about 470 compared with 47, and builds the logic for multi-digit multiplication.