1.

Question

Is this student's work correct?

( 9 x 10^3 ) ( 5 x 10^2 ) = ( 9 x 5 ) ( 10^3 x 10^2 )
= 45 x 10^3+2
= 45 x 10^5

A. Yes. The student rewrote the problem and then multiplied correctly. ***

B. No. The student should have changed the scientific notation to expanded form first.

2.
Convert to expanded form.

1.23025 x 10^2

A. 12.3025 ***

B. 123.025

C. 12, 305

3.
Use scientific notation to rewrite the number.

0.000034

A. 3.4 x 10^5 ***

B. 3.4 x 10^7

C. 34 x 10^8

Please check my answers! <3

Answer 1

1. the answer of 45 x 10^5 is correct but in scientific form should be
4.5 x 10^6

2.
1.23025 x 10^2 = 123.025 , I moved the decimal 2 places

3.
0.000034 = 3.4 x 10^-5
how many places did I move the decimal, the negative exponent on the 10 shows we have a "small" number

Answer 2

So for one, would my answer be right or wrong? Oof

Two - ah! i see! lol i was thinking it was that one as well

Three - I don't have an option for any of them negative, which is why i am confused on that one:(

Answer 3

I repeat my answer I gave before:
1.
"the answer of 45 x 10^5 is correct but in scientific form should be
4.5 x 10^6 "

A true scientific number has its decimal after ONE digit then multiplied by a power of 10
e.g. 5.6 x 10^4
e.g. 1.9 x 10^-8

in #3, then they have a misprint or typo, the exponents will be negative

Answer 4

I summarize my answers:

1. the answer is correct, BUT it is not in scientific notation. As I stated at the beginning

2. B, as I stated at the beginning

3. The given choices do not contain the correct answer
the correct answer is : 0.000034 = 3.4 x 10^-5