In a scientific notation, you have to put a decimal right after the first number (unless it is a zero). How many times you move the decimal from its original spot determines the answer. If you move the decimal forward that means you put a negative number
0.00000123 = 1.23 (moved the decimal point forward 6 times, so the answer is --->)
[tex] 1.23*10^{-6} [/tex]
