Http://www.icoachmath.com/math_dictionary/equivalent_equations.html
Here's a website that might help
Since they are the conjugates of each (9-a and 9+a are conjugates, or with any number replacing 9) , we multiply it by (9+i)/(9+i) to get (9+i)^2/(9-i^2)=(81+2i+i^2)/(9-(-1))=(81-1+2i)/(10)=80/10+2i/10=8+i/5. Conjugates work because they make i into i^2 (-1) without any of the sneaky i's in the middle!
The level of precision is given by the number of decimal places.
1.45 has a precision of 2 ( two decimal digits)
.0034 has a precision of 4 ( 4 decimal digits)
Numbers that end in zeros have negative precision:
100: has a precision of -2 ( 2 zeros)
15 : Whole numbers has precision 0.
From most precise to least precise:
.0034 - 1.45- 15 - 100