How do you do three hundred five and five tenths in expanded form?

To write the number 305.5 in expanded form, you would break it down into its component parts based on its place value. 305 is composed of 3 hundreds (300), 0 tens, and 5 ones. The .5 represents 5 tenths. Therefore, in expanded form, 305.5 would be written as 300 + 0 + 5 + 5/10.