What are some ways to measure when you don’t have a ruler?
Numbers and Math in Everyday Life
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There are some pretty standard items that you can use if you don’t have a ruler handy to measure something. Most of them are standard sizes, such as a sheet of paper measuring 8.5″ × 11″ so it will fit into most computer printers with ease. Here are a few of the best ways to do a quick measurement (remember, too—some of these are approximations):
 A sheet of standard letter paper is 8.5 by 11 inches long.
 U.S. paper currency measures 6 1/8 inches wide and 2 5/8 inches long.
 Most standard business cards measure 2 inches long by 3 ½ inches wide.
 Most postcards measure 3 inches by 5 inches.
 The diameter of a quarter is about one inch; the diameter of a penny is approximately 3/4 of an inch.
 A credit card is about 3 3/8 inches by 2 1/8 inches.
 A standard AA battery is about 2 inches long.
 The average adult toothbrush is about 7 inches long.