Browse · MathNet Print → South African Mathematics Olympiad South Africa algebra Problem Calculate 2015−(2015−(2015−(2015−1))). Solution — click to reveal 2015−(2015−(2015−(2015−1)))=2015−(2015−(2015−2014))=2015−(2015−1)=2015−2014=1.Alternatively, 2015−(2015−(2015−(2015−1)))=2015−2015+2015−2015+1=1. Final answer 1 Techniques Integers ← Previous problem Next problem →