Suppose you add a measurement of 7.2 mL to a measurement of 15.37 mL. How many decimal places should the answer have?
The answer must have
The thing to remember when dealing with addition or subtraction is that the result must be rounded to the same number of decimal places as the measurement with the least number of decimal places.
In your case, you have two measurements,
This means that the value you get by adding these two measurements must be rounded to one decimal place.
So, add the two measurements to get
#"7.2 mL " + " 15.37 mL" = "22.57 mL"#
Now, this number,
#22.5color(red)(cancel(color(black)(7))) implies 22.6#
Therefore, adding your two measurements will get you
#color(green)(|bar(ul(color(white)(a/a)color(black)("7.2 mL " + " 15.37 mL" = "22.6 mL")color(white)(a/a)|)))#