How do you write two and one tenth as a decimal in standard form?

The number two and one tenth as a decimal in standard form is written as 2.1 times 10 to the zeroth power. Raising a number to the zeroth power returns the number one, so the number above is equal to 2.1 times one, or simply 2.1.

According to Reference.com, to write a number in standard form — also called scientific notation — the number is expressed as a number between one and ten multiplied by some power of ten. To give an example, the number 3,000 in standard form would be equal to three times ten to the third power, which is the same as three times one thousand.