Scientific notation is writing a number 1-10 multiplied by ten to a certain power. We see that we can write the number 1.5 to fit this.
We want to multiply by ten to a negative power as the decimal has been moved to the left. Let's count how many times we need to move the decimal over to get to 1.5.
If we count this, we have to move 7 places to get the decimal in the right spot. Therefore, to write this in scientific notation, we would write 1.5×10^-7.
