Write this in standard form PHYSICS! please helllp

Can you please explain how to write the following numbers in standard form
0.2456
0.000000000005
4,576,123,546
900

In scientific notation, there is 1 number to the left of the decimal point.

The number of places that the decimal point is moved is the exponent of 10. If the decimal point is moved to the left, the exponent is positive. If the decimal point is moved to the right, the exponent is negative.

0.2456
Move the decimal point 1 places to the right = 2.456 * 10^-1

0.000000000005
Move the decimal point 12 places to the right = 5 * 10^-12 or 5.0 * 10^-12

4,576,123,546
Move the decimal point 9 places to the left = 4.576123546 * 10^9

900
Move the decimal point 2 places to the left = 9.0 * 10^2

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