Abooklet is made from 6 rectangular pieces of paper. each piece measures 297mm by 420mm. the mass of paper is 80g per m^2. what is the mass of the booklet

Alright, so the area of one paper is 297mm*420mm=124740mm^2. Multiplying that by 6 due to 6 sheets, we get 748440mm^2. Converting mm^2 to m^2, since we know that 1000mm=1m, we simply do (1m/1000m)^2=1m^2/1,000,000mm^2. Our equation is now
748440mm^2*1m^2/1,000,000mm^2=0.748440m^2 by crossing out the millimeters. Lastly, since it's 80g/1m^2, we multiply our number by that to get 59.8752g