question_answer 1)

                In a stack there are 5 books each of thickness 20 mm and 5 paper sheets each of thickness 0.016 mm. What is the total thickness of the stack?                              

Answer:

                Total thickness of books         \[=5\times 20\,mm\,=\,100\,mm\] Total thickness of paper sheets        \[=5\times 0.016\text{ }mm=0.080\text{ }mm\] \[\therefore \] Total thickness of the stack = Total thickness of books + Total thickness of paper sheets \[=100\,\,mm\,+0.080\,\,mm\] \[=(100=0.080)\,mm\] \[=100.080\,\,mm\] \[=1.0008\times {{10}^{2}}mm.\]