a x 10^4 + a x 10^2 = 24 240 where a is a number. Work out a x 10^4 - a x10^2 Give your answer in standard form.

From first principles: ax10^4 is the same as a0000. ax10^2 is the same as a00

So, a0000

          a00

     a0a00

If we look at this pattern and compare to the number in the question:

a0a00

  |  |

24240

the a0 corresponds to the numbers 24, so a is 2.4

2.4x10^4-2.4x10^2:

Write them out the same as before:

24000

    240 

23760

Then as standard form, put a decimal after the first digit

2.3760

then count how many places from the end of the number the deciaml has moved:

4

So, it's 2.3760x10^4

0 isn't necessary, so dont need to write it in our final answer

2.376x10^4

Answered by Joe B. Maths tutor

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