A+b=b+a
a+(b+c)=(a+b)+c
a+(b-c)=a+b-c
a-(b+c)=a-b-c
a-(b-c)=a-b+c
a*(b+c)=ab+ac
a*(b-c)=ab-ac
(a+b)*c=ca+cb
(a-b)*c=ca-cb
(a+b):c=a:c+b:c
(a-b):c=a:c-b:c
a*b=b*a
a*(b*c)=(a*b)*c
8.2t-4.4t=38.38
3.8t=38.38
t=38.38:3.8
t=10.1
(10.49-s):4.02=0.805
10.49-s=0.805*4.02
10.49-s=3.2361
s=10.49-3.2361
s=7.2539
(907*89 ) + (456*89 ) =122214
1) 907*89=81630
2) 456*89=40584
3) 81630+40584=122214