` 27 * (-53) +27 *47`
` =27 * (-53+47)`
` = 27 * (-6)`
` = -162`
-----
` 17/6 +26/(-12) - (-13)/39`
` = 17/6 - 26/12 +13/39`
` = 17/6 - 13/6 + 1/3`
` = 4/6 + 1/3`
` = 2/3 +1/3`
` = 3/3 = 1`
------
` 2/7 + (-5)/7 * 14/35 = 2/7 - 5/7 * 2/5 = 2/7 - 10/35 = 2/7 -2/7`
` =0`
--------
` -1/4 + [-5/8 +1/4]`
` = -1/4 -5/8 +1/4`
` = (-1/4 +1/4) -5/8`
` = -5/8`