Math Is Fun Forum

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Scientific Notation to Decimal

College Algebra
Section R.2

Write each number as a decimal.

A. 2.1 x 10^(4)

Answer: 21,000

To obtain the answer, I moved the decimal point 4 places to the right.
Why move the decimal point to the right?

B. 3.26 x 10^(-5)

Answer: 0.0000326

To obtain the answer, I moved the decimal point 5 places to the left.
Why move the decimal point to the left?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,198

Re: Scientific Notation to Decimal

If you followed the other post on this you'll see we are just reversing those examples.

eg. 2.1 x 10^(4) = 2.1 x 10000 = 21000. The point has moved four places because that's what multiplying by 10000 does.

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Scientific Notation to Decimal

I thought the decimal point moves the number of spaces indicated by the power of 10.

Yes? No?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,198

Re: Scientific Notation to Decimal

The number of noughts after the 1, and the power of ten amount to the same thing.

And if the power of ten is negative a similar rule applies.

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Scientific Notation to Decimal

Really? I didn't know this fact. Math is a great road of information.