Answer:
Explanation:
The goal in scientific notation is to express a value in terms of a number that contains a single unit before the decimal point.
Examples:
10000: 1.0 x 10^4
23456: 2.3456x10^4
In both cases, the x10^4 is telling us to multiply the first number by 10,000. 10^4 is the same as 10x10x10x10 = 10,000
The justification for scientific notation is that is makes expression large and small numbers much easier, as well as reduces errors due to an incorrectly placed decimal.
An example: Divide 2500000000 by 5000. That would normally require setting up a long-hand division problem that not only wastes paper and pencil, but is also prone to decimal point errors.
Do the same problem with scientific notation:
Count the places you want to move the decimal point backwards to just beyond the 5 in 2500000000. It takes nine steps to move the decimal point to between the 2 and 5: 2.5 followed by 8 zeros. That's a total of next steps to go in front of the 5. This is written 2.5 x 10^9
5000 is represented by 5.0x10^4
Now when we divide the same numbers, but in scientific format, it is easier to see the answer:
(2.5x10^9)/(5.0x10^4)
2.5/5 = 0.5
10^9/10^4 = 10^5 [The exponents are subtracted when dividing with exponents: 9-4 = 5]
Put them together to find the final answer: 0.5x10^5
Then move the decimal point one spot to the right and reduce the exponent by 1:
5.0x10^4
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Add exponents when multiplying: 10^3 x 10^5 = 10^8 (3+5=8)
Subtract when dividing: 10^7/10^2 = 10^5 (7-2=5)
Multiply when there is an exponent raised to another exponent: (10^4)^3 = 10^12 (4x3 = 12)