Solution

AGIMNRT= MIGRANT
AGIMNRT= MARTING
AGIMNRT+E=EMIGRANT
AGIMNRT+E=REMATING
AGIMNRT+P=TRAMPING
AGIMNRT+S=MIGRANTS
AGIMNRT+U=MATURING
AGIMNRT+S=SMARTING
AGIMNRT+M=TRAMMING