Maths help

What is the answer to this question?

(2.52 x 10^5) / (4 x 10^-3)

First I got 63 x 10^8 then I made the 63 10 times smaller so its in standard form

Reply 1

username2820734

Work it out using (2.52/4) * (10^5--3)

Reply 2

yemenia16

Original post by jt1212

What is the answer to this question?

(2.52 x 10^5) / (4 x 10^-3)

First I got 63 x 10^8 then I made the 63 10 times smaller so its in standard form

Answer=63000000 -> 6.3 x10^7

Reply 3

jt1212

Original post by yemenia16

Answer=63000000 -> 6.3 x10^7

Whys it 6.3 x10^7 and not 6.3 x 10^9

because I divided 63 by 10 to get 6.3 shouldn't I divide the other side ?

Reply 4

username3460126

Yh since you make it ten times smaller you take one away from the powers so it would be

6.3 ×10^7
:smile:

Reply 5

jt1212

Original post by A.N123

Yh since you make it ten times smaller you take one away from the powers so it would be

6.3 ×10^7
:smile:

So what are we essentially doing to the other side? DIviding multiplying?

So when you divide you take a power and when you multiply you add a power

Reply 6

username3460126

Original post by jt1212

So when you divide you take a power and when you multiply you add a power

Yes! But only when you need to make it ten times smaller :smile:

Reply 7

NotNotBatman

Original post by jt1212

What is the answer to this question?

(2.52 x 10^5) / (4 x 10^-3)

First I got 63 x 10^8 then I made the 63 10 times smaller so its in standard form

\frac{2.52 \times 10^5}{4 \times 10^{-3}} = \frac{2.52}{4} \times \frac{10^5}{10^{-3}}

Because the order of multiplication and division can be swapped, as division is the same as multiplying by the reciprocal of a number i.e.

\frac{a}{b} = a \times \frac{1}{b}

Now, it seems like you've understood the power rule. So for

\frac{2.52}{4} = 0.63

the way you have to do this is to write everything in standard form. change 0.63 into the form

6.3 \times 10^n

Then multiply the entire expression; you'll have

6.3 \times 10^n \times \frac{10^5}{10^{-3}}

Using the rules

a^n \times a^m = a^{n+m}

and

\frac{a^n}{a^m} = a^{n-m}

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