Mr. Gibson Science Classes – all disciplines

September 12th & 13th

SY-2011/2012

Sig. FigsAddition & SubtractionAdding

Expanded numbers with

proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

5.0 cm 5.355 cm

+ 5.68 cm = ? cm

Step 1: Carry out the addition first…

Sig. FigsAddition & SubtractionAdding

Expanded numbers with

proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

5.0 cm 5.355 cm

+ 5.68 cm = 16.035 cm

Step 1: Carry out the addition first…

Sig. FigsAddition & SubtractionAdding

Expanded numbers with

proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

5.0 cm 5.355 cm

+ 5.68 cm = 16.035 cm

Step 2: Locate the number in the group being added together that has the fewest decimal places.

Sig. FigsAddition & SubtractionAdding

Expanded numbers with

proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

5.0 cm 5.355 cm

+ 5.68 cm = 16.035 cm

Step 3: round off the answer so that it has the SAME number of decimal places as the number in the problem with the fewest.

Sig. FigsAddition & SubtractionAdding

Expanded numbers with

proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

5.0 cm 5.355 cm

+ 5.68 cm = 16.0 cm

In this example the answer will only have one decimal place just like 5.0 in the problem did.

Sig. FigsAddition & SubtractionAdding

Expanded numbers with

proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

10.2 cm 10.0 cm

+ 10 cm = ? cm

Step 1: Add up the numbers;

Step 2: Find the number with the smallest number of decimal places;

Step 3: Round-off the answer so that its decimal places = the number in the problem with the lowest decimal places.

Sig. FigsAddition & Subtraction

Subtracting Expanded

numbers with proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

10.2550 cm

- 5.005 cm = 5.2500 cm

Step 1: subtract the numbers;

Sig. FigsAddition & Subtraction

Subtracting Expanded

numbers with proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

10.2550 cm - 5.005 cm = 5.2500 cm

Step 2: Find the number with the smallest number of decimal places;

Sig. FigsAddition & Subtraction

Subtracting Expanded

numbers with proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

10.2550 cm - 5.005 cm = 5.2500 cm

Step 3: Round off your answer such that it is the same as the number in the problem with the smallest number of decimal places;

Sig. FigsAddition & Subtraction

Subtracting Expanded

numbers with proper number of Sig Figs in

the sum._______________

We will add the following three numbers shown to the right to illustrate the rules for sig. figs.

10.2550 cm - 5.005 cm = 5.250 cm

Step 3: Round off your answer such that it is the same as the number in the problem with the smallest number of decimal places;

Sig. FigsAddition & Subtraction

Adding Expanded numbers with

proper number of Sig Figs in the

sum._______________

• Now go get a Chemistry text book – turn to page 41 and do problems 35 & 36.•Be prepared to put your work on the board when called.

Step 1: Find the number with the smallest number of decimal places;

Step 2: Add up or subtract the numbers as indicated by the problem;

Step 3: Round-off the answer so that its decimal places = the number in the problem with the lowest decimal places.