A first encounter
Play with numbers.
Ages 7 and up. Change a number and watch the picture—and the answer—change with it. No old notation required.
People in Edo-period Japan asked the same simple questions we do: “How many?” “How can we share them?” Questions like these are a doorway into wasan.
The plus sign means “put together.” The equals sign means both sides have the same value.
Build a triangle
One circle in the top row, two in the next, then three. How many altogether?
1 + 2 + 3 = 6
There are 6 circles altogether. Each new row has one more.
Share them equally
Make three equal groups. Does everyone have the same number?
Share 12 circles equally among three people.
4 + 4 + 4 = 12
Each person gets 4. Put the groups back together and you have 12 again.
Double it!
To double a number, add another group of the same size.
Start with one circle and double it twice.
2 + 2 = 4
Doubling means adding another group of the same size.
1 → 2 → 4
How many legs?
Change the number of cranes and turtles, then count the legs.
A crane has two legs. A turtle has four.
2 + 2 + 4 = 8
That makes 8 legs altogether. Each circle stands for one leg.
For parents and teachers: these small-number activities introduce ideas that lead into wasan. They are not transcriptions of historical problem statements. The calculator links lead to more general versions with larger numbers and broader conditions.