How do you write 1.00 as a percentage

Exactly the same way you write any other number as a percentage . . .
multiply it by 100, then write a 'percent' sign ( % ) after the new number.

Examples:

-- Write 0.01 as a percentage . . . 1%

-- Write 0.5 as a percentage . . . 50%

-- Write 3.27 as a percentage . . . 327%

The answer to your question:

To write 1.00 as a percentage, multiply it by 100 . . . 1.00 ==> 100% .

Ithink it would be 1.24 pounds