Given: 7x10^-4 Use the rule for exponent: a^-m=1/10^m, where a and m are any real numbers and a≄0, e.g. 10^-1=1/10^1=1/10=0.1, 10^-2=1/10^2=1/100=0.01, and 10^-3=1/10^3=1/1,000=0.001.
So, 10^-4=1/10^4=1/10,000=0.0001
Thus, 7x10^-4=7x0.0001=0.0007
The answer is: 7x10^-4=0.0007*
*: Notice that the number of zeros,4, placed in front of "7" is equal to the number of its power,4. Don't miss the decimal point.