Comparing sets - L.1
Can anyone count without knowing numbers? It seems impossible to do so. However, our ancestors were able to do it. They did not name any numbers so how was it possible?
Counting with stones - L.2
First, counted objects were represented by some other smaller objects. Then, people drew line segments and other figures. This way the symbols representing concrete numbers were finally invented.
Binary system - L.3
As quantity increased, it became difficult to create new figures for them. It was also difficult to remember them. The solution came with grouping objects and counting the groups. those groups.
Base three system - L.4
Groups concisted of single element or smaler identical groups but the quantity of the members in each group had to reminde the same. But, how the result had been written?
Decimal system - L.5
Having ten fingers people created symbols for the numbers from 1 to 10. Any forgot symbol could be, that way, told using fingers. As the result people decided to use grouping by ten.
Shapes of numbers - L.6
Can numbers have shapes?
- Let's examine some properties of numbers
Cubes and cubic numbers - L.7
What's so special in cubes?
Similarly to squares cubs have equal size of their sides
What about cuboids? Are they special?
3D Shaping - L.8
By turning our bloc
and eliminating some balls we can construct more shapes.

Adding objects - L.9
Add decimal numbers using their representations in the form of ball sets
Adding numbers - L.10

Let's add some numbers with a mouse
Addition algorithm - L.11
Let's add numbers fast and efficiently.
Substraction algorithm - L.12

Let's substract numbers fast and efficiently.
Multiplicate by adding - L13

Multiplication is nothing but a difrent form of addition.
Multiplication of Integers - L14.

Multiplication is understandable. Obviously it does not depend of the order of numbers.
Multiplication Algorithm - L15.

Multiplication algorithm is not difficult but to master it you may need some practice.