A decimal number is simply a way of representing a number in such a way that the place value of each digit is ten times that of the digit to its right. A decimal representation does not require a decimal point. So the decimal representation of 45 is 45, exactly as in the question.
0.45
It is not a decimal number.
15.045
1.45
Forty-five point eight zero seven. (it represents forty-five and eight hundred seven thousandths)
0.45
The number 46.5 is the written decimal form for forty six and five tenths.
It is 0.45
The decimal number for forty five over fifty eight (45/58) is: 0.775862
0.040
0.45
47.5
0.5102
It is not a decimal number.
It is "one and forty-five hundredths", the decimal fraction hyphenated.
45/100 = .45
0.45