math

6.4 x 10^11 + 2.85 x 10^11 ( finding the sum written in scientific notation?)
- 9.25 x 10^11 (my answer)
- 9.25 x 10^22
- 92.5 x 10^-10
- 92.5 x 10^12
3 x 10^20/ 4 x 10^5 (write in scientific notation)
- 7.5 x 10^3
- 0.75 x 10^4 (my answer)
- 7.5 x 10^14
- 7.5 x 10^15
(6.2 x 10^-8)(5 x 10^-2) *write in scientific notation*
- 3.1 x 10^16
- 3.1 x 10^-9
- 3.1 x 10^-11
- 3.1 x 10^-10 (my answer)
~Thanks! I really don't understand this

  1. 👍 0
  2. 👎 0
  3. 👁 193
  1. review scientific notation. There is a number and a power of 10.

    the number must be between 1 and 10. (Less than 10)

    When adding, the powers of 10 must be the same, just as you need a common denominator to add fractions. Then you can just add the numbers as usual, keeping the same power of 10.

    When multiplying, you multiply the numbers, and add the exponents.

    So, let's proceed.

    6.4 x 10^11 + 2.85 x 10^11
    The powers are the same, so just add.
    (6.4+2.85)x10^11
    9.25x10^11

    3 x 10^20/ 4 x 10^5
    divide numbers and subtract powers (because it's division, not multiplication)
    (3/4)x10^(20-5)
    = 0.75x10^15
    But, the number has to be at least 1.0, so if we multiply it by 10, we have to also divide by 10 to keep things unchanged. Dividing by 10 means lowering the power by 1. So now we have
    7.5x10^14

    (6.2 x 10^-8)(5 x 10^-2)
    (6.2*5)x10^(-8 + -2)
    31.0x10^-10
    But, the number must be less than 10, so we have to divide by 10, and raise the power to compensate:
    3.1x10^-9

    If things are still unclear, google scientific notation and you will find lots of other discussions. Maybe one of them will present things in a way that is clearer for you.

    1. 👍 0
    2. 👎 0
    posted by Steve

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    Hi everyone! I am extremely struggling with this questions and was hoping someone would go over them with me. Thank you! 1. Which of the following expressions is written in scientific notation? a. 73.4 x 10^5 b. 0.09 × 10^7 c. 80

    asked by Tia on January 29, 2015
  2. math

    1. Which of the following expressions is written in scientific notation? 1. 73.4 x 105 2. 0.09 × 107 3. 80 x 103 4. 4.22 x 10–3 2. Which of the following is 0.0000000708 written in scientific notation? 1. 7.08 x 10–8 2. 7.8 x

    asked by ruby on January 31, 2013
  3. Math PLZ HELP

    1. Which of the following expressions is written in scientific notation? 1. 73.4 x 105 2. 0.09 × 107 3. 80 x 103 4. 4.22 x 10–3 2. Which of the following is 0.0000000708 written in scientific notation? 1. 7.08 x 10–8 2. 7.8 x

    asked by SAMHAM on January 31, 2013
  4. Math! Please Check My Awnser!

    Hello! I need some help with math! I have tried to do this but I am unsure about my answers. My I will identify my answers with a "

    asked by Electro on January 14, 2014
  5. Algebra Help!!

    Find an example of scientific notation in real life Explain why the number was written in scientific notation. Create a multiplication problem with scientific notation

    asked by Katie A on October 4, 2011
  6. Math

    Determine if the number is written in scientific notation. If not, explain; 3 x 100⁻⁶. A. No; it is not written as a power of 10. B. No; the first factor is not a number between 1 and 10. C. Yes; the number is written in

    asked by D on March 14, 2018
  7. Algebra 1

    I am having trouble with a few questions....Wondering if you could help...My answers have the *** by them..... 1. A lab is growing bacteria in a culture dish. The amount of bacteria in the dish doubles every 3 hours. Initially,

    asked by Brittany on September 29, 2016
  8. Math

    1. –(10)^–1 (1 point) –1/10*** -1/-1^10 1/10 10 2. 1/c^-5 (1 point) c^5 5c –c^5*** –5/c 3. What is the value of y^-5/x^-3 for x = 2 and y = –4? (1 point) 10/3 128 -1/128 –128*** 4. Is the number written in scientific

    asked by Bethany on April 22, 2016
  9. 7th grade Math quick help Ms. Sue

    Can you check to see if tese are right? 1. What is 0.68 written as a simplified fraction? 68/100 17/25 100/68 34/25 2. Mrs. Whimsey’s class is having a pizza party. If there are 16 students and 4 pizzas cut into 8 slices, what

    asked by Delilah on October 3, 2012
  10. algebra

    i need help. not saying these are right, i just tried my best, could someone check them for me? (NOT ALL ARE ANSWERED) 1. (-5)^-1 A. - 1/5 ********** B. -5 C. 5 D. 1/5 2. (-8.3) ^0 A. 1 B. -1 C. 0 D. -8.3 ********** 3. -1/a^-2 A.

    asked by kindaneedhelpASAP on February 21, 2019

More Similar Questions