5.30 and 5.3 are equivalent to 5.300. You see, if there is a zero at the end of each decimals, that is nothing. Zeroes or nothing. But if it were to be a number, for example: 5.3003, it would be different. 5.3000000000000000000000000000000000 is the same thing to 5.3 Ask me if you don't understand. I hope it helped...
Two or more decimal numbers are said to be equivalent decimals, when they name the same value (or same amount). For example, the decimals: 0.2 = 0.20 = 0.200 = 0.2000 etc. Thus by successive addition of zeros after the decimal part of the number after the decimal point means the same number and hence are equivalent. Therefore, the decimals: 5.3, 5.30, 5.300, 5.3000 etc are all equivalent.