Oblicz. a) 1 1/5 * 1 2/3

`"a)"`

`1 1/5*1 2/3*1/7+(1 1/7)^2` `=strike(6)^2/strike(5)^1 * strike(5)^1/strike(3)^1 * 1/7 + (8/7)^2` `=2/1 * 1/7 + 64/49=2/7 + 64/49=14/49 + 64/49` `=78/49` `=1 29/49`

`"b)"`

`(2 1/6 - 2/3)^2 - 2 1/5=(13/6 - 4/6)^2 - 11/5=81/36 - 11/5=405/180 - 396/180=9/180=1/20`  

`"c)"`

`10 - 2 * (3 1/5 - 2 1/4 * 1/3)` `=10 - 2 * (16/5 - 3/4)=10 - 2 * ( 64/20 - 15/20)` `=10 - strike(2)^1 * 49/strike(20)^10` `=10 - 49/10` `=10 - 4 9/10` `=5 1/10`

`"d)"`

`(7/3 - 5/12 + 1 1/2) : ( 2 3/4 - 5/6)` `=(28/12 - 5/12 + 1 6/12) : (2 9/12 - 10/12)` `=(28/12 - 5/12 + 18/12) : (33/12 - 10/12)=` `41/12 : 23/12=41/strike(12)^1 * strike(12)^1/23=41/23`  `=1 18/23`