Significant Figures Math Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

medium
A chemist measures 25.0025.00 mL of solution using a burette and 0.50.5 mL using a dropper. She adds them. What is the total volume with correct significant figures?

Solution

  1. 1
    Values: 25.0025.00 mL (44 sig figs, precise to hundredths) and 0.50.5 mL (11 sig fig, precise to tenths).
  2. 2
    For addition, align by decimal place: the less precise is 0.50.5 mL (tenths place).
  3. 3
    Sum: 25.00+0.5=25.525.00 + 0.5 = 25.5 mL, reported to the tenths place.

Answer

Total volume =25.5= 25.5 mL.
In addition and subtraction, the result is limited to the least precise decimal place, not the fewest significant figures. The dropper only gives tenths precision, so the tenths place is the limit of the sum — the hundredths from the burette are lost.

About Significant Figures

Significant figures are the meaningful digits in a measured quantity, reflecting its precision.

Learn more about Significant Figures →

More Significant Figures Examples

Example 1 easy

Count the significant figures in each number: (a) [formula], (b) [formula], (c) [formula].

Example 2 medium

A rectangle measures [formula] cm by [formula] cm. Calculate the area to the correct number of signi

Example 3 easy

Round each to [formula] significant figures: (a) [formula], (b) [formula], (c) [formula].

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