The G' for the reaction Citrate Isocitrate is + 6.64 kJ mol -1 = + 1.59

The ΔG°' for the reaction Citrate → Isocitrate is + 6.64 kJ mol^-1 =  + 1.59 kcal mol^-1. The ΔG°' for the reaction Isocitrate → α-Ketoglutarate is - 267 kJ mol^-1 = -63.9 kcal mol^-1. What is the ΔG°' for the conversion of citrate to α-ketoglutarate? Is that reaction exergonic or endergonic, and why?