Find the inch marks on the ruler
Look for the longest lines, which usually mark whole inches
Count the spaces between whole-inch marks
Use the shorter lines to measure fractions of an inch
The longest line between inches is usually 1/2 inch
The next shorter lines are usually 1/4 inch and 3/4 inch
The smallest lines are usually 1/8 inch or 1/16 inch
Start at the zero mark, not the edge of the ruler
Read the number where the object ends
Combine whole inches and fractions if needed