# Maths

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#1
Can someone help me work out this question?

M= 7.1 x 10 to the power of 6
N = 3.2 x 10 to the power of -3

Work out in each case giving your answer in standard from to 3sf

a) mn

b) m over n

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4 years ago
#2
multiply the numbers (7.1 times 3.2) and add the exponents (+6 - 3) to get M*N = (7.1*3.2) x 10^(6-3) = 22.72 x 10^3

Then to get it back in standard form, you need the first bit to look like "X.XX", so re-write 22.72x10^3 as 2.272x10^4. Note that you divide the first bit by ten and then raise the exponent by one.

The same method can be applied for the second method. Give it a go. (remember 1/(x^a) == x^(-a), i.e. the exponent sign goes negative when you move from denominator to numerator)
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4 years ago
#3
mn = (7.1 x10 ^6 ) x (3.2 x10^-3) first multiply 7.1 by 3.2 then consider what happens to the powers of 10 for example 500 x 20 = 10,000 and notice whats happened to them in this sum and apply it to your own and similarly for part b) m/n look at for example 5000/50 = 100
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#4
Thank you!😄

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