Is scientific notation a way to express very large or small numbers?
yes...it helps show both very small and large amounts.
Are numbers expressed in scientific notation using exponents true or false?
Indeed they are exponential. So, true.
250,000
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count groups of three and subtract on, as the count ends just before the whole number, 2 in this case, or count decimal places from the left and end just befor that whole number on the right
= 2.5 X 105
===========that count you make is the value of the exponent
How do you write 0.000408 in scientific notation?
0.000408 can be written in scientific notation as 4.08 x 10^-4.