Common Core: 8th Grade Math : Grade 8

Study concepts, example questions & explanations for Common Core: 8th Grade Math

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Example Questions

Example Question #31 : Expressions & Equations

Select the number that is equal to five times ten to the seventh power. 

 

Possible Answers:

Correct answer:

Explanation:

Five times ten to the seventh power can be written numerically as the following:

When a number between one and ten is multiplied by a power of ten it is said to be written in scientific notation. This number is currently written in scientific notation.

Even though this appears to be a challenging math problem (i.e. because we have a power of ten), we can simply move our decimal place after the five, or , over  spaces to the right using zeros as place holders. 

Add commas and simplify.

Example Question #9 : Use Powers Of 10 To Estimate Quantities: Ccss.Math.Content.8.Ee.A.3

Select the number that is equal to nine times ten to the third power. 

 

Possible Answers:

Correct answer:

Explanation:

Nine times ten to the third power can be written numerically as the following:

When a number between one and ten is multiplied by a power of ten it is said to be written in scientific notation. This number is currently written in scientific notation.

Even though this appears to be a challenging math problem (i.e. because we have a power of ten), we can simply move our decimal place after the nine, or , over  spaces to the right using zeros as place holders. 

Add commas and simplify.

Example Question #10 : Use Powers Of 10 To Estimate Quantities: Ccss.Math.Content.8.Ee.A.3

Select the number that is equal to nine times ten to the second power. 

 

Possible Answers:

Correct answer:

Explanation:

Nine times ten to the second power can be written numerically as the following:

When a number between one and ten is multiplied by a power of ten it is said to be written in scientific notation. This number is currently written in scientific notation.

Even though this appears to be a challenging math problem (i.e. because we have a power of ten), we can simply move our decimal place after the nine, or , over  spaces to the right using zeros as place holders. 

Add commas and simplify.

Example Question #32 : Expressions & Equations

Select the number that is equal to nine times ten to the tenth power. 

 

Possible Answers:

Correct answer:

Explanation:

Nine times ten to the tenth power can be written numerically as the following:

When a number between one and ten is multiplied by a power of ten it is said to be written in scientific notation. This number is currently written in scientific notation.

Even though this appears to be a challenging math problem (i.e. because we have a power of ten), we can simply move our decimal place after the nine, or , over  spaces to the right using zeros as place holders. 

Add commas and simplify.

Example Question #33 : Expressions & Equations

Select the number that is equal to four times ten to the eighth power. 

Possible Answers:

Correct answer:

Explanation:

Four times ten to the eighth power can be written numerically as the following:

When a number between one and ten is multiplied by a power of ten it is said to be written in scientific notation. This number is currently written in scientific notation.

Even though this appears to be a challenging math problem (i.e. because we have a power of ten), we can simply move our decimal place after the four, or , over  spaces to the right using zeros as place holders. 

Add commas and simplify.

Example Question #34 : Expressions & Equations

Convert the given value to scientific notation.

Possible Answers:

Correct answer:

Explanation:

Scientific notation is used to simplify exceptionally complex numbers and to quickly present the number of significant figures in a given value. The value is converted to an exponent form using base ten, such that only a single-digit term with any given number of decimal places is used to represent the significant figures of the given value. Non-significant zeroes can be omitted from the leading term, and represented only in the base ten exponent.

The given number has four significant figures (3123), so there will be four digits multiplied by the base ten term.

To generate the single-digit leading term the decimal must be placed after the first 3. Then count the digits to the right of the decimal (123). Our ten will be raised to the power of three.

Our final answer is 

Example Question #1 : Scientific Notation And Significant Figures

Convert the given value to scientific notation.

Possible Answers:

Correct answer:

Explanation:

Scientific notation is used to simplify exceptionally complex numbers and to quickly present the number of significant figures in a given value. The value is converted to an exponent form using base ten, such that only a single-digit term with any given number of decimal places is used to represent the significant figures of the given value. Non-significant zeroes can be omitted from the leading term, and represented only in the base ten exponent.

The given number has three significant figures (321), so there will be three digits multiplied by the base ten term.

To generate the single-digit leading term the decimal must be placed after the 3 (3.21). Then count the digits to the left of the decimal (moving from right to left, these are 3, 0, 0). Our ten will be raised to the power of negative three because there are three digits to the left of the final decimal placement.

Our final answer is .

Example Question #41 : Expressions & Equations

Convert the given value to scientific notation.

Possible Answers:

Correct answer:

Explanation:

Scientific notation is used to simplify exceptionally complex numbers and to quickly present the number of significant figures in a given value. The value is converted to an exponent form using base ten, such that only a single-digit term with any given number of decimal places is used to represent the significant figures of the given value. Non-significant zeroes can be omitted from the leading term, and represented only in the base ten exponent.

The given number has five significant figures (100.43), so there will be five digits multiplied by the base ten term.

To generate the single-digit leading term the decimal must be placed after the 1 (1.0043). Then count the digits to the right of the decimal to determine the change in decimal placement (the decimal moves past the two zeroes). Our ten will be raised to the power of two because there are two digits to the right of the final decimal placement.

Our final answer is 

Example Question #31 : High School Chemistry

Convert the given value to scientific notation.

Possible Answers:

Correct answer:

Explanation:

Scientific notation is used to simplify exceptionally complex numbers and to quickly present the number of significant figures in a given value. The value is converted to an exponent form using base ten, such that only a single-digit term with any given number of decimal places is used to represent the significant figures of the given value. Non-significant zeroes can be omitted from the leading term, and represented only in the base ten exponent.

The given number has three significant figures (60.1), so there will be three digits multiplied by the base ten term.

To generate the single-digit leading term the decimal must be placed after the 6 (6.01). Then count the digits to the right of the decimal to determine the change in decimal placement (the decimal moves past the zero only). Our ten will be raised to the power of one because there is only one digit to the right of the final decimal placement.

Our final answer is 

Example Question #32 : High School Chemistry

Convert the given value to standard notation.

Possible Answers:

Correct answer:

Explanation:

Converting a value from scientific notation to standard notation is a simple matter of multiplication.

Since we are always multiplying by a base ten term, the value of the exponent determines the increase/decrease in terms of orders of magnitude. In this case, an exponent of 4 indicates a four-fold increase in order of magnitude. Some may find it easiest to determine the answer by simply adjusting the decimal four digits to the right, adding zeroes as necessary.

Whether you choose to multiply or to simply shift the decimal, the final answer will be .

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