6-
1
. . .
, 1, .
1,2,3,4,5...
1.
.
, . : 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
.
.
: a + b = b + a
a b 0.
:
90 + 20 = 20 + 90 = 110
.
:
(a + b) + c = a + (b + c)
:
6 + 4 + (3 + 2) = 6 + (4 + 3) + 2 = (6 + 4) + 3 + 2 = 15
, ,
!
, .
a + 0 = 0 + a = a
2
. .
.
a b = b a
:
11 4 = 4 11 = 44
, , .
a (b c) = (a b) c
, .
a 0 = 0
0 a b c = 0
, .
a 0 = 0
0 a b c = 0
, .
(a + b) c = a c + b c
: 8 (6 + 5) = 8 6 + 8 5 = 48 + 40 = 88
, , , .
: (a − b) c = a c − b c
|
|
: 8 (6 - 5) = 8 6 - 8 5 = 48 - 40 = 8
1 .
a 1 = a
: 18 1=18
3
a ,
.
:
a a a.
:
4
:
.