### Tutorial 1.5: Part 3

Calculating to the correct number of significant figures.

How do we properly round the result of this calculation?

$423 ml \times \frac{23 g}{ml}$

Here is the calculator result:

$423 ml \times \frac{23 g}{ml} = 9729 g$

423 has 3 significant figures and 23 has 2 significant figures, so we round to 2 significant figures ( the less precise measurement). Our answer is:

$$9.7 \times 10^3 g$$

How do we properly round the result of this calculation?

$0.0041 ml \times \frac{2.89 g}{ml}$

Here is the calculator result:

$0.0041 ml \times \frac{2.89 g}{ml} = 0.011849 g$

0.0041 has 2 significant figures and 2.89 has 3 significant figures, so we round to 2 significant figures ( the less precise measurement). Our answer is:

$$1.2 \times 10^{-2} g$$