The tiles · Grades 2 to 4
Rectangle
A number is a rectangle: multiplication as area
On the way This tile's page is up; the playable version follows.
What your child does
Build a number as a rectangle of dots: 6 is 2 by 3, and also 1 by 6. Your child drags out a grid until it holds exactly the number asked for, and every rectangle that works is a factor pair made visible.
This is the bridge from groups-of addition to multiplication, and the ground for factors, primes and area later. The grid is boundless; the camera follows the corner your child is dragging.
What it teaches
- Counting rows and columns
- Multiplication as arrays and area
- Area by counting squares
- Area by multiplying
- Factors and multiples
This one is teaching ground: the board either comes right or it does not, and there is no wrong rule to name. The tiles that follow it do the diagnosing.
The other tiles
Stacks · Carry · Make Ten · Chart · Odometer · Time · Fraction · Brick
Cardinal Math watches for all of these, every day.
Inside the app the same patterns are caught as your child plays, across the whole of K to grade 5, and explained to you in plain words. One price, no ads, no streaks. Coming to iPhone and iPad.
Tell me when it's out