`a, 8 2/3 + 2,5 = 26/3 + 5/2 = 67/6`
`b, 18 2/17 + 15/23 + 1 15/17 + 3/19 + 8/23`
= `( 2/17 + 15/17 ) + ( 18 + 1 ) + ( 15/23 + 8/23 ) + 3/19`
= `1 + 19 + 1 + 3/19`
= `21 + 3/19`
= `402/19`
`c, -2 2/3 - 0,2 + 1,75 - 5/6`
= `-8/3 - 1/5 + 7/4 - 5/6`
= `-43/15 + 11/12`
= `-39/20`
`d, ( 19/21 - 2/3 ) . 2,8`
= `5/21 . 14/5`
= `14/21`
`e, 3/11 . 2 2/3 - 1,75`
= `3/11 . 8/3 - 7/4`
= `8/11 - 7/4`
= `-45/44`
`g, ( 3/4 + 0,5 ) . ( 4/5 - 0,6 )`
= `5/4 . 1/5`
= `1/4`
`h, 3 1/9 . 12 5/7 - 9 5/7 . 3 1/9`
= `28/9 . 89/7 - 68/7 . 28/9`
= `28/9 . ( 89/7 - 68/7)`
= `28/9 . 3`
= `28/3`
`j, 3,2 . 15/64 - ( 4/5 + 2/3 ) : 3 2/3`
= `3/4 - 22/15 : 11/3`
= `3/4 - 2/5`
= `7/20`
