Step-by-step explanation:
Choose a small section of the book to measure. This section should be near the spine of the book, where the pages are tightly bound together.
Hold the ruler perpendicular to the book's spine, so that it is parallel to the pages you want to measure.Carefully close the book so that the pages you want to measure are sandwiched between the ruler and the spine.
Read the measurement on the ruler where the top and bottom of the pages meet. This measurement represents the thickness of the entire stack of pages.
Estimate the number of pages in the stack by dividing the height of the stack by the measurement you just took. For example, if the stack is 2 centimeters high and the measurement you took is 0.1 centimeters, then you can estimate that the stack contains approximately 20 pages.
Finally, divide the thickness of the entire stack by the number of pages in the stack to estimate the thickness of one paper. For example, if the stack is 0.1 centimeters thick and contains 20 pages, then the estimated thickness of one paper is 0.005 centimeters or 0.05 millimeters.