Mathematics - Functions Question with Solution | TestHub

Since $\lfloor t+1\rfloor =\lfloor t\rfloor +1$, for $0<x<1$ we need $-1\le x+y<0$, and for $1\le x<2$ we need $0\le x+y<1$. Each vertical section has length 1 and the two strips each have width 1, hence area 2.