Unit 1 Review 8th grade math

Lucy estimated that it would take 4,000 grains of sand to make a pound. That would mean that each grain of sand weighs 1/4000 of a pound. In decimal form, that weight would be 0.00025 of a pound. Express this in scientific notation?

• 2.5 × 10^–4 pounds

• 4 × 10^–3 pounds

• 2.5 × 10^–3 pounds

• 2.5 × 10^–5 pounds

Which section(s) would the numbers –7, 8, –4 be placed in according to the chart?

• Irrational

• Integers

• Whole

• Natural

Robert and Dora need to write 4,300,000,000 using scientific notation. Robert claims that 4,300,000,000 = 4.3 x 10⁸ and Dora claims that 4,300,000,000 = 4.3 x 10⁹. Whose number is correct and why?

• Robert’s number is correct because when converting 4,300,000,000, the decimal would be located between the 4 and the 3, and the original decimal point in the standard form moves to the left 8 places.

• Robert’s number is correct because when converting 4,300,000,000, the decimal would be located between the 4 and the 3, and the power of 10 is determined by the number of zeros.

• Dora’s number is correct because when converting 4,300,000,000, the decimal would be located between the 4 and the 3, and the original decimal point in the standard form moves to the left 9 places.

• Dora’s number is correct because when converting 4,300,000,000, the decimal would be located between the 4 and the 3, and the power of 10 is always the number of zeros plus 1.

Tags

CCSS.6.EE.A.1

A researcher measured approximately 0.005123 grams of bacteria in a sample. How is this number expressed in scientific notation?

• 5.123 × 10³ grams

• 5123 × 10^–6 grams

• 0.5123 × 10^–2 grams

• 5.123 × 10^–3 grams

Tags

CCSS.6.EE.A.2

CCSS.6.EE.A.4

A microscopic cell measures 3.8 × 10–4 centimeters in diameter. What is this number in standard decimal notation?

• 12,000,000 = 1.2 × 10⁷

• –74.308 < –0.74 × 10³

• 2 × 10⁴ < 20,000

• 5.3 × 10^–2 = –0.053

The number 0 is located in which set of numbers? ​

• Rational

• Integer

• Whole

• Natural

List the numbers in order from the day of greatest increase in depth to the day of the greatest decrease in depth.

• Tuesday, Thursday, Friday, Monday, Wednesday

• Tuesday, Wednesday, Thursday, Friday, Monday

• Tuesday, Thursday, Wednesday, Friday, Monday

• Thursday, Tuesday, Wednesday, Monday, Friday

Write the following numbers in ascending order.

​​–2 3/8, –0.85, 4/3 , 1 2/5, –8/6, 0.8

• –2 3/8, –8/6, –0.85, 0.8, 4/3 , 1 2/5

• –8/6, –0.85, 0.8, 4/3 , 1 2/5, –2 3/8

• –2 3/8, 1 2/5, 4/3 , 0.8, –0.85, –8/6

• 1 2/5, 4/3 , 0.8, –0.85, –8/6, –2 3/8

Which number set represents Section A in the Venn diagram?

• Rational

• Real

• Integers

• Irrational

A microscopic cell measures 3.8 x 10^-3 centimeters in diameter. What is this number in standard notation?

• 0.000038

• 0.00038

• 0.0038

• 0.038