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
Answer:
the answer is 45
Step-by-step explanation:

When you're multiplying by a power of 10 such as 100, the decimal point moves two places to the right. Note that this corresponds with the number of zeroes in 100. Of course our number is going to get bigger, not smaller, which means we'd have to be going right. If we multiplied by something like 0.001, we'd also be going two places, just going smaller and to the left.