What is 0.00025 in scientific notation?

Answer 1

It is 2.5 x 10-4. In engineering notation, it is 2.5E-4.
2.5 * 10-4
Well, you didn't put a decimal point in there, so you'd drop the superfluous zeros to the left of the 25, and 25 in scientific notation is .......25, or if you wanted to push scientific notation past where it is normally used, it would be 2.5 X10^1

But I suspect you meant 0.000025, yes? That would be 2.5 X 10^-5

For very small numbers, any decimal fraction is expressed in scientific notation by counting the number of spaces you need to move the decimal point to the right to put it after the first non-zero integer. Move the decimal point to the right of that first integer and then make that number X 10 to the negative power of the number places you moved the decimal.

0.002 = 2 X 10^-3

0.00254 = 2.54 X 10^-3

0.000000003424 = 3.424 X 10 ^-9

For very large numbers, you count the number of spaces you need to move the decimal to the left so it ends up to the right of the largest column, and move the decimal there, multiplying it by 10 to the power of the number of spaces you moved the decimal.

2000 = 2 X 10^3

2100 = 2.1 X 10^3

123000000000 = 1.23 X 10^11