Significant Figures - Rules and Rounding off

A baker weighs out 205.378 grams of flour for a recipe, but the scale used in the kitchen only measures to 4 significant figures.

What should the displayed weight be, rounded correctly? (No need to write the units)

Which of the following has 4 significant figures?

• 0.00400

• 7.080

• 0.07

• 100

Zeros between nonzero digits are:

• Always significant

• Never significant

• Only significant if there’s a decimal point

• • Sometimes significant

A nurse prepares a solution with a concentration of 1.2863 mol/L, but the prescription sheet requires the value to be rounded to 2 significant figures.

What concentration should the nurse write down? (No need to write the units)

How many significant figures are in 3.200 × 10³?

• 2

• 3

• 4

• 5

Round 6.374 to 3 significant figures.

Round 0.04689 to 2 significant figures.

Round 91.567 to 3 significant figures.

What is 2.499 rounded to 2 significant figures?

A pharmacist is preparing a medication and measures a liquid solution to be 0.056786 liters. However, the prescription requires the volume to be reported with 3 significant figures only, as specified by standard medical documentation procedures.

What volume should the pharmacist record on the prescription? (No need to write the units)