Question

To what decimal place should each answer be rounded?

How many significant figures does the rounded answer have?

(a) $101cm-99.1cm=1.9cm$ (unrounded) After rounding, the answer should be reported to the ( ones place / tenths place / hundredths place ) and thus has ($1$ significant figure / $2$ significant figure / $3$ significant figure )

(b) $0.5atm+9.8atm=10.3atm$ (unrounded) After rounding, the number should be reported to the ( ones place / tenths place / hundredths place ) and thus has ($1$ significant figure / $2$ significant figure / $3$ significant figure )

Answer 1

Explanation for correct answer:

Step-1: Rounded off the value:

The basis for rounding off entails that the place value immediately lower in hierarchy to the place value to be rounded to is considered;

If the digit which occupies this place value is greater or equal to $5$; it is rounded to $1$ and added to the required place value.

If otherwise, it is rounded to zero, $0$ and added to the required digit.

Step-2: Rounded off the place value:

$101cm-99.1cm=1.9cm$

Rounding off to ones place $=2cm$ with one significant figure.

Rounding off to tenth place $=1.9cm$ with two significant figures.

Rounding off to hundredths place $=1.90cm$ with three significant figures.

Step-3: Rounded off the place value:

$0.5atm+9.8atm=10.3atm$

Rounding off to ones place $=10atm$ with two significant figure.

Rounding off to tenth place $=10.3atm$ with three significant figures.

Rounding off to hundredths place $=10.30cm$ with four significant figures.