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 required decimal representation is 210, exactly as in the question.
210
4/210 = 0.0190476190476
You can write this as 210/1.
In decimal form, 210% is 2.1.
210,000.
210
210,000,000
210% = 2.1 as a decimal and 21/10 as a fraction
210 over 1000 which equals 21 over 100
werwerewrewrwerwe
-210
210,726