Question

skill practice 2
significant figures practice
name: shawnee henner
date: 9/30/25
hour: 3rd
perform the following operations and give answers in the correct number of significant figures. if the question is in scientific notation, then please use scientific notation in your answer.

1. 200.00 + 125.2 = 325.2
2. 12,020 + 6006 =
3. 0.003450 + 0.0140 =
4. 0.820 - 0.030 = 0.790
5. (240,900)(120.0) =
6. 340/12.5 =
7. (2.450 x 10^6)(2.0 x 10^6) =
8. (5.369 x 10^12)/(2.89 x 10^7) =

Explanation:

Step1: Add numbers

$12020 + 6006=18026$
Since the least precise value (12020 and 6006) has no decimal - places, the answer 18026 is already in the correct number of significant figures.

Step2: Add decimal numbers

$0.003450+0.0140 = 0.01745$
The number 0.0140 has four significant figures and is least precise in the hundred - thousandths place. Rounding 0.01745 to four significant figures gives 0.0175.

Step3: Multiply numbers

$240900\times120.0 = 28908000$
The number 120.0 has four significant figures. Writing the answer in scientific notation to four significant figures: $2.891\times 10^{7}$

Step4: Divide numbers

$340\div12.5=27.2$
12.5 has three significant figures, and the result 27.2 also has three significant figures.

Step5: Multiply numbers in scientific notation

$(2.450\times 10^{6})\times(2.0\times 10^{6})=(2.450\times2.0)\times10^{6 + 6}=4.9\times 10^{12}$
2.0 has two significant figures, so the product is rounded to two significant figures.

Step6: Divide numbers in scientific notation

$\frac{5.369\times 10^{12}}{2.89\times 10^{7}}=\frac{5.369}{2.89}\times10^{12 - 7}\approx1.86\times 10^{5}$
2.89 has three significant figures, so the result is rounded to three significant figures.

Answer:

1. $18026$
2. $0.0175$
3. $2.891\times 10^{7}$
4. $27.2$
5. $4.9\times 10^{12}$
6. $1.86\times 10^{5}$